186 results on '"Haplochromine"'
Search Results
2. Geographic variation in opsin expression does not align with opsin genotype in Lake Victoria cichlid populations
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Daniel Shane Wright, Roy Meijer, Roel vanEijk, Wicher Vos, Ole Seehausen, and Martine E. Maan
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ecological speciation ,haplochromine ,LWS ,sensory drive ,Ecology ,QH540-549.5 - Abstract
Abstract Sensory adaptation to the local environment can contribute to speciation. Aquatic environments are well suited for studying this process: The natural attenuation of light through water results in heterogeneous light environments, to which vision‐dependent species must adapt for communication and survival. Here, we study visual adaptation in sympatric Pundamilia cichlids from southeastern Lake Victoria. Species with blue or red male nuptial coloration co‐occur at many rocky islands but tend to be depth‐differentiated, entailing different visual habitats, more strongly at some islands than others. Divergent visual adaptation to these environments has been implicated as a major factor in the divergence of P. pundamilia and P. nyererei, as they show consistent differentiation in the long‐wavelength‐sensitive visual pigment gene sequence (LWS opsin). In addition to sequence variation, variation in the opsin gene expression levels may contribute to visual adaptation. We characterized opsin gene expression and LWS genotype across Pundamilia populations inhabiting turbid and clear waters, to examine how different mechanisms of visual tuning contribute to visual adaptation. As predicted, the short‐wavelength‐sensitive opsin (SWS2b) was expressed exclusively in a population from clear water. Contrary to prediction however, expression levels of the other opsins were species‐ and island‐dependent and did not align with species differences in LWS genotype. Specifically, in two locations with turbid water, the shallow‐water dwelling blue species expressed more LWS and less RH2A than the deeper‐dwelling red species, while the opposite pattern occurred in the two locations with clear water. Visual modeling suggests that the observed distribution of opsin expression profiles and LWS genotypes does not maximize visual performance, implying the involvement of additional visual tuning mechanisms and/or incomplete adaptation. OPEN RESEARCH BADGE This article has earned an Open Data Badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at https://hdl.handle.net/10411/I1IUUQ.
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- 2019
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3. Visual adaptation and microhabitat choice in Lake Victoria cichlid fish
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Daniel Mameri, Corina van Kammen, Ton G. G. Groothuis, Ole Seehausen, and Martine E. Maan
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sensory drive ,habitat choice ,haplochromine ,ecological speciation ,colour vision ,Science - Abstract
When different genotypes choose different habitats to better match their phenotypes, genetic differentiation within a population may be promoted. Mating within those habitats may subsequently contribute to reproductive isolation. In cichlid fish, visual adaptation to alternative visual environments is hypothesized to contribute to speciation. Here, we investigated whether variation in visual sensitivity causes different visual habitat preferences, using two closely related cichlid species that occur at different but overlapping water depths in Lake Victoria and that differ in visual perception (Pundamilia spp.). In addition to species differences, we explored potential effects of visual plasticity, by rearing fish in two different light conditions: broad-spectrum (mimicking shallow water) and red-shifted (mimicking deeper waters). Contrary to expectations, fish did not prefer the light environment that mimicked their typical natural habitat. Instead, we found an overall preference for the broad-spectrum environment. We also found a transient influence of the rearing condition, indicating that the assessment of microhabitat preference requires repeated testing to control for familiarity effects. Together, our results show that cichlid fish exert visual habitat preference but do not support straightforward visual habitat matching.
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- 2019
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4. Geographic variation in opsin expression does not align with opsin genotype in Lake Victoria cichlid populations.
- Author
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Wright, Daniel Shane, Meijer, Roy, Eijk, Roel, Vos, Wicher, Seehausen, Ole, and Maan, Martine E.
- Subjects
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VISUAL environment , *GENOTYPES , *GENE expression - Abstract
Sensory adaptation to the local environment can contribute to speciation. Aquatic environments are well suited for studying this process: The natural attenuation of light through water results in heterogeneous light environments, to which vision‐dependent species must adapt for communication and survival. Here, we study visual adaptation in sympatric Pundamilia cichlids from southeastern Lake Victoria. Species with blue or red male nuptial coloration co‐occur at many rocky islands but tend to be depth‐differentiated, entailing different visual habitats, more strongly at some islands than others. Divergent visual adaptation to these environments has been implicated as a major factor in the divergence of P. pundamilia and P. nyererei, as they show consistent differentiation in the long‐wavelength‐sensitive visual pigment gene sequence (LWS opsin). In addition to sequence variation, variation in the opsin gene expression levels may contribute to visual adaptation. We characterized opsin gene expression and LWS genotype across Pundamilia populations inhabiting turbid and clear waters, to examine how different mechanisms of visual tuning contribute to visual adaptation. As predicted, the short‐wavelength‐sensitive opsin (SWS2b) was expressed exclusively in a population from clear water. Contrary to prediction however, expression levels of the other opsins were species‐ and island‐dependent and did not align with species differences in LWS genotype. Specifically, in two locations with turbid water, the shallow‐water dwelling blue species expressed more LWS and less RH2A than the deeper‐dwelling red species, while the opposite pattern occurred in the two locations with clear water. Visual modeling suggests that the observed distribution of opsin expression profiles and LWS genotypes does not maximize visual performance, implying the involvement of additional visual tuning mechanisms and/or incomplete adaptation. OPEN RESEARCH BADGE: This article has earned an Open Data Badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at https://hdl.handle.net/10411/I1IUUQ. [ABSTRACT FROM AUTHOR]
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- 2019
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5. Strong species structure but weak geographical structure in demersal Lake Victoria cichlids
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van Rijssel, Jacco C, Moser, Florian N, Mwaiko, Salome, and Seehausen, Ole
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Haplochromine ,species delineation ,Speciation ,Business Manager projecten Midden-Noord ,RAD-tag sequencing ,570 Life sciences ,biology ,Lake Victoria ,Business Manager projects Mid-North ,Hybridization ,cichlids - Abstract
Studying phenotypic and genetic differentiation between very young species can be very informative with regard to learning about processes of speciation. Identifying and characterizing genetic species structure and distinguishing it from spatial genetic structure within a species is a prerequisite for this and is often not given sufficient attention. Young radiations of cichlid fish are classical speciation study systems. However, it is only during the past decade that population genomics based on next-generation sequencing has begun to provide the power to resolve species and distinguish speciation from spatial population structure for the youngest of these radiations. The Lake Victoria haplochromine cichlids constitute the youngest large cichlid fish radiation, probably
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- 2022
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6. Of bars and stripes: A Malawi cichlid hybrid cross provides insights into genetic modularity and evolution of modifier loci underlying colour pattern diversification
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Axel Meyer, Sabine Urban, Claudius F. Kratochwil, Jan Gerwin, Integrative Evolutionary Biology, Institute of Biotechnology, and Helsinki Institute of Life Science HiLIFE
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QTL mapping ,0106 biological sciences ,Malawi ,Color ,transgressive segregation ,Biology ,Quantitative trait locus ,010603 evolutionary biology ,01 natural sciences ,Transgressive segregation ,Divergence ,PLEISTOCENE DESICCATION ,03 medical and health sciences ,horizontal stripes ,Cichlid ,ddc:570 ,Adaptive radiation ,DIVERGENCE ,Genetics ,Animals ,LAKE VICTORIA ,IN-VIVO ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Hybrid ,standing genetic variation ,QUANTITATIVE TRAIT LOCI ,0303 health sciences ,IDENTIFICATION ,BACKCROSS QTL ANALYSIS ,food and beverages ,Cichlids ,biology.organism_classification ,ADAPTIVE RADIATION ,QTL mapping, hybridzation, standing genetic variation, horizontal stripes, vertical bars, transgressive segregation ,Haplochromine ,Phenotype ,hybridzation ,Evolutionary biology ,vertical bars ,1181 Ecology, evolutionary biology ,FISHES ,Pseudotropheus ,human activities ,HYBRIDIZATION - Abstract
Understanding the origins of phenotypic diversity among closely related species remains an important largely unsolved question in evolutionary biology. With over 800 species, Lake Malawi haplochromine cichlid fishes are a prominent example of extremely fast evolution of diversity including variation in coloration. Previously, a single major effect gene, agrp2 (asip2b), has been linked to evolutionary losses and gains of horizontal stripe patterns in cichlids, but it remains unknown what causes more fine-scale variation in the number and continuity of the stripes. Also, the genetic basis of the most common color pattern in African cichlids, vertical bars, and potential interactions between the two color patterns remain unknown. Based on a hybrid cross of the horizontally striped Lake Malawi cichlid Pseudotropheus cyaneorhabdos and the vertically barred species Chindongo demasoni we investigated the genetic basis of both color patterns. The distribution of phenotypes in the F2 generation of the cross indicates that horizontal stripes and vertical bars are independently inherited patterns that are caused by two sets of genetic modules. While horizontal stripes are largely controlled by few major effect loci, vertical bars are a highly polygenic trait. Horizontal stripes show substantial variation in the F2 generation that, interestingly, resemble naturally occurring phenotypes found in other Lake Malawi cichlid species. Quantitative trait loci (QTL) mapping of this cross reveals known (agrp2) and unknown loci underlying horizontal stripe patterns. These findings provide novel insights into the incremental fine-tuning of an adaptive trait that diversified through the evolution of additional modifier loci.
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- 2021
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7. Strong species structure but weak geographical structure in demersal Lake Victoria cichlids
- Author
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van Rijssel, Jacco C., Moser, Florian N., Mwaiko, Salome, Seehausen, Ole, van Rijssel, Jacco C., Moser, Florian N., Mwaiko, Salome, and Seehausen, Ole
- Abstract
Studying phenotypic and genetic differentiation between very young species can be very informative with regard to learning about processes of speciation. Identifying and characterizing genetic species structure and distinguishing it from spatial genetic structure within a species is a prerequisite for this and is often not given sufficient attention. Young radiations of cichlid fish are classical speciation study systems. However, it is only during the past decade that population genomics based on next-generation sequencing has begun to provide the power to resolve species and distinguish speciation from spatial population structure for the youngest of these radiations. The Lake Victoria haplochromine cichlids constitute the youngest large cichlid fish radiation, probably <20,000 years old. Earlier work showed that communities of rocky reef cichlids are composed of many reciprocally monophyletic species despite their very recent origins. Here, we build on this work by studying assemblages of offshore demersal cichlids, adding analyses of within-species spatial structure to the sympatricspecies structure. We sampled seven multispecies communities along a 6-km-long transect from one side of the Mwanza Gulf to the other side. We investigated whether phenotypically diagnosed putative species are reciprocally monophyletic and whether such monophyly is stable across species geographic ranges. We show that all species are genetically strongly differentiated in sympatry, that they are reciprocally monophyletic, and that monophyly is stable across distribution ranges. We found significant differentiation between geographically distinct populations in two species, but no or weak isolation by distance. We further found subtle but significant morphological differences between all species and a linear relationship between genomic and morphological distance which suggests that differences in morphology begin to accumulate after speciation has already affected genome-wide restrict
- Published
- 2022
8. Identification of a novel sex determining chromosome in cichlid fishes that acts as XY or ZW in different lineages
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Anna F. Feller, Vera Ogi, Joana I. Meier, Ole Seehausen, Feller, Anna F [0000-0001-5786-7658], Seehausen, Ole [0000-0001-6598-1434], Meier, Joana I [0000-0001-7726-2875], and Apollo - University of Cambridge Repository
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0106 biological sciences ,0303 health sciences ,biology ,Chromosome ,Interspecific competition ,Aquatic Science ,Sex determination ,Lake Victoria ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Haplochromine ,03 medical and health sciences ,Cichlid ,Evolutionary biology ,Advances in Cichlid Research IV ,Lake Malawi ,570 Life sciences ,Identification (biology) ,14. Life underwater ,Clade ,human activities ,Heterogametic sex ,Cichlid fishes ,030304 developmental biology - Abstract
Funder: The Branco Weiss Fellowship – Society in Science; doi: http://dx.doi.org/10.13039/501100001710, UNLABELLED: Sex determination systems are highly conserved among most vertebrates with genetic sex determination, but can be variable and evolve rapidly in some. Here, we study sex determination in a clade with exceptionally high sex chromosome turnover rates. We identify the sex determining chromosomes in three interspecific crosses of haplochromine cichlid fishes from Lakes Victoria and Malawi. We find evidence for different sex determiners in each cross. In the Malawi cross and one Victoria cross the same chromosome is sex-linked but while females are the heterogametic sex in the Malawi species, males are the heterogametic sex in the Victoria species. This chromosome has not previously been reported to be sex determining in cichlids, increasing the number of different chromosomes shown to be sex determining in cichlids to 12. All Lake Victoria species of our crosses are less than 15,000 years divergent, and we identified different sex determiners among them. Our study provides further evidence for the diversity and evolutionary flexibility of sex determination in cichlids, factors which might contribute to their rapid adaptive radiations. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10750-021-04560-7.
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- 2021
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9. Species specificity and sexual dimorphism in tooth shape among the three sympatric haplochromine species in Lake Kivu cichlids
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Wilson W. L. Jere, Philippe Munyandamutsa, Daud Kassam, and Austin Mtethiwa
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0106 biological sciences ,elliptic fourier analysis ,Zoology ,Haplochromis ,Haplochromis kamiranzovu ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,stomatognathic system ,lcsh:QH540-549.5 ,Littoral zone ,Ecology, Evolution, Behavior and Systematics ,Original Research ,030304 developmental biology ,Nature and Landscape Conservation ,0303 health sciences ,Ecology ,biology ,Pelagic zone ,tooth shape ,biology.organism_classification ,Sexual dimorphism ,Haplochromine ,stomatognathic diseases ,Habitat ,Lake Kivu ,Sympatric speciation ,lcsh:Ecology - Abstract
Tooth shape is used to differentiate between morphologically similar species of vertebrates, including fish. This study aimed to quantify tooth shape of three sympatric species: Haplochromis kamiranzovu, H. insidiae, and H. astatodon endemic to Lake Kivu, whose existing identification criteria are currently only qualitative. A quantitative tooth shape analysis was performed based on digitized tooth outline data with a subsequent elliptic Fourier analysis to test for differences among the three species. We looked at crown shape and size differences within H. kamiranzovu and H. insidiae at geographical, habitat, and gender levels. No comparison at habitat level was done for H. astatodon because it is found only in littoral zone. The analysis revealed significant tooth shape differences among the three species. Haplochromis astatodon had a significantly longer major cusp height and a longer and larger minor cusp than that of H. insidiae. It had also a longer major cusp height and a longer and larger minor cusp than that of H. kamiranzovu. Tooth shape differences of H. kamiranzovu and H. insidiae species were not significantly different between littoral and pelagic fish (p > .05) while differences were significant between southern and northern Lake Kivu populations (p .05). Tooth shape was also significantly different with sharp teeth for males compared with females of southern populations versus northern ones. These shape‐ and size‐related differences between sexes suggest differences in the foraging strategies toward available food resources in the lake habitat. Further research should explain the genetic basis of the observed pattern., We quantified tooth shape trait to distinguish the three morphological similar Haplochromis kamiranzovu, H. insidiae, and H. astatodon) endemic to Lake Kivu.
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- 2020
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10. Strong species structure but weak geographical structure in demersal Lake Victoria cichlids
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Haplochromine ,species delineation ,Speciation ,Business Manager projecten Midden-Noord ,RAD-tag sequencing ,Lake Victoria ,Business Manager projects Mid-North ,Hybridization ,cichlids - Abstract
Studying phenotypic and genetic differentiation between very young species can be very informative with regard to learning about processes of speciation. Identifying and characterizing genetic species structure and distinguishing it from spatial genetic structure within a species is a prerequisite for this and is often not given sufficient attention. Young radiations of cichlid fish are classical speciation study systems. However, it is only during the past decade that population genomics based on next-generation sequencing has begun to provide the power to resolve species and distinguish speciation from spatial population structure for the youngest of these radiations. The Lake Victoria haplochromine cichlids constitute the youngest large cichlid fish radiation, probably
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- 2022
- Full Text
- View/download PDF
11. Expression variations in Ectodysplasin-A gene (eda) may contribute to morphological divergence of scales in Haplochromine cichlids
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Anna Duenser, Christian Sturmbauer, Maximilian Wagner, Wolfgang Gessl, Ehsan Pashay Ahi, and Sandra Bračun
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0106 biological sciences ,Appendage ,0303 health sciences ,Scale (anatomy) ,biology ,Stickleback ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Haplochromine ,03 medical and health sciences ,Cichlid ,Evolutionary biology ,Gene expression ,Ectodysplasin A ,Gene ,030304 developmental biology - Abstract
BackgroundElasmoid scales are one of the most common dermal appendages and can be found in almost all species of bony fish differing greatly in their shape. Whilst the genetic underpinnings behind elasmoid scale development have been investigated, not much is known about the mechanisms involved in the shaping of scales. To investigate the links between gene expression differences and morphological divergence, we inferred shape variation of scales from two different areas of the body (anterior and posterior) stemming from ten haplochromine cichlid species from different origins (Lake Tanganyika, Lake Malawi, Lake Victoria and riverine). Additionally, we investigated transcriptional differences of a set of genes known to be involved in scale development and morphogenesis in fish.ResultsWe found that scales from the anterior and posterior part of the body strongly differ in their overall shape, and a separate look on scales from each body part revealed similar trajectories of shape differences considering the lake origin of single investigated species. Above all, nine as well as 11 out of 16 target genes showed expression differences between the lakes for the anterior and posterior dataset, respectively. Whereas in posterior scales four genes (dlx5, eda, rankl and shh) revealed significant correlations between expression and morphological differentiation, in anterior scales only one gene (eda) showed such a correlation. Furthermore, eda displayed the most significant expression difference between species of Lake Tanganyika and species of the other two younger lakes. Finally, we found genetic differences in downstream regions of eda gene (e.g. in the eda-tnfsf13b inter-genic region) that are associated with observed expression differences. This is reminiscent of a genetic difference in the eda-tnfsf13b inter-genic region which leads to gain or loss of armour plates in stickleback.ConclusionThese findings provide evidence for cross-species transcriptional differences of an important morphogenetic factor, eda, which is involved in formation of ectodermal appendages. These expression differences appeared to be associated with morphological differences observed in the scales of haplochromine cichlids indicating potential role of eda mediated signal in divergent scale morphogenesis in fish.
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- 2021
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12. Differential use of multiple genetic sex determination systems in divergent ecomorphs of an African crater lake cichlid
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Bettina Fischer, Benjamin P. Ngatunga, Shane A. McCarthy, George F. Turner, Iliana Bista, Alexandra M. Tyers, Asilatu Shechonge, M. Emília Santos, Eric A. Miska, Richard Durbin, Hubert Denise, Mingliu Du, Tyler Linderoth, Grégoire Vernaz, Hannah Munby, and Martin J. Genner
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Haplochromine ,Speciation ,Evolutionary biology ,Cichlid ,media_common.quotation_subject ,Crater lake ,Gene duplication ,Tandem exon duplication ,Biology ,Allele ,biology.organism_classification ,Genome ,media_common - Abstract
African cichlid fishes not only exhibit remarkably high rates of speciation but also have some of the fastest evolving sex determination systems in vertebrates. However, little is known empirically in cichlids about the genetic mechanisms generating new sex-determining variants, what forces dictate their fate, the demographic scales at which they evolve, and whether they are related to speciation. To address these questions, we looked for sex-associated loci in full genome data from 647 individuals of Astatotilapia calliptera from Lake Masoko, a small isolated crater lake in Tanzania, which contains two distinct ecomorphs of the species. We identified three separate XY systems on recombining chromosomes. Two Y alleles derive from mutations that increase expression of the gonadal soma-derived factor gene (gsdf) on chromosome 7; the first is a tandem duplication of the entire gene observed throughout much of the Lake Malawi haplochromine cichlid radiation to which A. calliptera belongs, and the second is a 5 kb insertion directly upstream of gsdf. Both the latter variant and another 700 bp insertion on chromosome 19 responsible for the third Y allele arose from transposable element insertions. Males belonging to the Masoko deep-water benthic ecomorph are determined exclusively by the gsdf duplication, whereas all three Y alleles are used in the Masoko littoral ecomorph, in which they appear to act antagonistically among males with different amounts of benthic admixture. This antagonism in the face of ongoing admixture may be important for sustaining multifactorial sex determination in Lake Masoko. In addition to identifying the molecular basis of three coexisting sex determining alleles, these results demonstrate that genetic interactions between Y alleles and genetic background can potentially affect fitness and adaptive evolution.
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- 2021
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13. Contribution of opsins and chromophores to cone pigment variation across populations of Lake Victoria cichlids
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Elodie Wilwert, Rampal Etienne, Martine Maan, Louis Van de Zande, Etienne group, Van de Zande lab, and Maan group
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Male ,Opsins ,biology ,Pigmentation ,media_common.quotation_subject ,Pundamilia ,Rod Opsins ,Zoology ,Cichlids ,Aquatic Science ,biology.organism_classification ,Ecological speciation ,Haplochromine ,Lakes ,Speciation ,food ,Sympatric speciation ,Cichlid ,Animals ,food.nutrient ,Adaptation ,Vitamin A ,Ecology, Evolution, Behavior and Systematics ,Vitamin a1 ,media_common - Abstract
Adaptation to heterogeneous sensory environments has been implicated as a key parameter in speciation. Cichlid fish are a textbook example of divergent visual adaptation, mediated by variation in the sequences and expression levels of cone opsin genes (encoding the protein component of visual pigments). In some vertebrates including fish, visual sensitivity is also tuned by the ratio of Vitamin A1/A2-derived chromophores (i.e. the light-sensitive component of the visual pigment, bound to the opsin protein), where higher proportions of A2 cause a more red-shifted wavelength absorbance. Here, we explore variation in chromophore ratios across multiple cichlid populations in Lake Victoria, using as a proxy the enzyme CYP27C1 that catalyses the conversion of Vitamin A1-into A2. We focus on sympatric Pundamilia cichlids, where species with blue or red male coloration co-occur at multiple islands, but occupy different depths and consequently different visual habitats. In the red species, we found higher cyp27c1 expression in populations from turbid-water than from clear-water locations, but there was no such pattern in the blue species. Across populations, differences between the sympatric species in cyp27c1 expression had a consistent relationship with species differences in opsin expression patterns, but the red/blue identity reversed between clear- and turbid-water locations. To assess the contribution of heritable versus environmental causes of variation, we tested whether light manipulations induce a change in cyp27c1 expression in the laboratory. We found that cyp27c1 expression was not influenced by experimental light conditions, suggesting that the observed variation in the wild is due to genetic differences. Establishing the biological importance of this variation requires testing the link between cyp27c1 expression and A1/A2 ratios in the eye, as well as its consequences for visual performance.
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- 2021
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14. Genetic diversity and historical demography in Bellamya gastropods from the Lake Victoria ecoregion reveal early and severe population collapse
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Nathan V. Whelan and Ellen E. Strong
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0106 biological sciences ,0301 basic medicine ,Gastropoda ,Population ,Context (language use) ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,Ecoregion ,Cichlid ,Adaptive radiation ,Genetics ,Animals ,Humans ,education ,Ecosystem ,Ecology, Evolution, Behavior and Systematics ,Demography ,education.field_of_study ,biology ,Ecology ,Genetic Variation ,Historical demography ,Cichlids ,biology.organism_classification ,Biological Evolution ,Haplochromine ,Lakes ,Phylogeography ,030104 developmental biology - Abstract
Understanding the interplay between ecological and population genetic processes through space and time is a central goal of landscape genetics. However, most studies that place diversification dynamics in an ecological context have focused on vertebrates, leaving a significant gap in our understanding of the effects of ecosystem change on community composition and demography of invertebrates. In the East African Rift System, cichlid fishes have emerged as a powerful model system for understanding adaptive radiation (Kornfield & Smith, 2000), but few studies have examined diversification of other taxa. In this issue of Molecular Ecology, Van Bocxlaer et al. (2020) use landscape genetic approaches to model historical demography and diversification of viviparid gastropods in the Lake Victoria ecoregion. They show that while phylogeographic patterns are similar between the two, viviparids and cichlids have responded in very different ways to the climatic upheavals of the Pleistocene and that their responses have been at least partially asynchronous. Viviparids have experienced population collapse 30- to 50-fold more severe than that seen in haplochromine cichlids from the region, and population declines began 100K years earlier, prior to the last glacial maximum (~15,000-18,000 years ago). Their results reveal a new facet to the profound and lasting impacts of Pleistocene climate change on the modern fauna of the Lake Victoria ecoregion and its ability to respond to current human-mediated stressors.
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- 2020
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15. Divergence in larval jaw gene expression reflects differential trophic adaptation in haplochromine cichlids prior to foraging
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Christian Sturmbauer, Wolfgang Gessl, Pooja Singh, Ehsan Pashay Ahi, Anna Duenser, and Organismal and Evolutionary Biology Research Programme
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0106 biological sciences ,0301 basic medicine ,Gene regulatory network ,Haplochromine cichlids ,01 natural sciences ,Tanzania ,Evolutionsbiologi ,Adaptive radiation ,Morphogenesis ,Gene Regulatory Networks ,Phylogeny ,Trophic level ,1184 Genetics, developmental biology, physiology ,Gene Expression Regulation, Developmental ,Cichlids ,Reference Standards ,Adaptation, Physiological ,East African lakes ,Larva ,Trophic specialization ,Research Article ,Evolution ,education ,Modularity ,Biology ,010603 evolutionary biology ,03 medical and health sciences ,Cichlid ,QH359-425 ,Animals ,14. Life underwater ,Pharyngeal jaw ,jaw development ,Ecology, Evolution, Behavior and Systematics ,Ecosystem ,Evolutionary Biology ,Gene Expression Profiling ,Genetic Variation ,Feeding Behavior ,biology.organism_classification ,Gene expression profiling ,Haplochromine ,Lakes ,stomatognathic diseases ,030104 developmental biology ,Jaw ,Evolutionary biology ,Pharynx ,Adaptation - Abstract
Background Understanding how variation in gene expression contributes to morphological diversity is a major goal in evolutionary biology. Cichlid fishes from the East African Great lakes exhibit striking diversity in trophic adaptations predicated on the functional modularity of their two sets of jaws (oral and pharyngeal). However, the transcriptional basis of this modularity is not so well understood, as no studies thus far have directly compared the expression of genes in the oral and pharyngeal jaws. Nor is it well understood how gene expression may have contributed to the parallel evolution of trophic morphologies across the replicate cichlid adaptive radiations in Lake Tanganyika, Malawi and Victoria. Results We set out to investigate the role of gene expression divergence in cichlid fishes from these three lakes adapted to herbivorous and carnivorous trophic niches. We focused on the development stage prior to the onset of exogenous feeding that is critical for understanding patterns of gene expression after oral and pharyngeal jaw skeletogenesis, anticipating environmental cues. This framework permitted us for the first time to test for signatures of gene expression underlying jaw modularity in convergent eco-morphologies across three independent adaptive radiations. We validated a set of reference genes, with stable expression between the two jaw types and across species, which can be important for future studies of gene expression in cichlid jaws. Next we found evidence of modular and non-modular gene expression between the two jaws, across different trophic niches and lakes. For instance, prdm1a, a skeletogenic gene with modular anterior-posterior expression, displayed higher pharyngeal jaw expression and modular expression pattern only in carnivorous species. Furthermore, we found the expression of genes in cichlids jaws from the youngest Lake Victoria to exhibit low modularity compared to the older lakes. Conclusion Overall, our results provide cross-species transcriptional comparisons of modularly-regulated skeletogenic genes in the two jaw types, implicating expression differences which might contribute to the formation of divergent trophic morphologies at the stage of larval independence prior to foraging. Electronic supplementary material The online version of this article (10.1186/s12862-019-1483-3) contains supplementary material, which is available to authorized users.
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- 2019
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16. East African cichlid lineages (Teleostei: Cichlidae) might be older than their ancient host lakes: new divergence estimates for the east African cichlid radiation
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Frederic Dieter Benedikt Schedel, Zuzana Musilová, and Ulrich K. Schliewen
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0106 biological sciences ,0301 basic medicine ,Lamprologini ,Time Factors ,Evolution ,Lineage (evolution) ,Zoology ,DNA, Mitochondrial ,Tanzania ,010603 evolutionary biology ,01 natural sciences ,Lamprologus ,03 medical and health sciences ,Orthochromis ,Cichlid ,East African cichlid radiation (EAR) ,QH359-425 ,Animals ,Clade ,Molecular clock ,Phylogeny ,Ecology, Evolution, Behavior and Systematics ,Congo River ,African Great Lakes ,biology ,Tugenchromis ,Genetic Variation ,Cichlids ,biology.organism_classification ,Biological Evolution ,Haplochromine ,Lakes ,Genes, Mitochondrial ,030104 developmental biology ,Congo ,Calibration ,Research Article - Abstract
Background Cichlids are a prime model system in evolutionary research and several of the most prominent examples of adaptive radiations are found in the East African Lakes Tanganyika, Malawi and Victoria, all part of the East African cichlid radiation (EAR). In the past, great effort has been invested in reconstructing the evolutionary and biogeographic history of cichlids (Teleostei: Cichlidae). In this study, we present new divergence age estimates for the major cichlid lineages with the main focus on the EAR based on a dataset encompassing representative taxa of almost all recognized cichlid tribes and ten mitochondrial protein genes. We have thoroughly re-evaluated both fossil and geological calibration points, and we included the recently described fossil †Tugenchromis pickfordi in the cichlid divergence age estimates. Results Our results estimate the origin of the EAR to Late Eocene/Early Oligocene (28.71 Ma; 95% HPD: 24.43–33.15 Ma). More importantly divergence ages of the most recent common ancestor (MRCA) of several Tanganyika cichlid tribes were estimated to be substantially older than the oldest estimated maximum age of the Lake Tanganyika: Trematocarini (16.13 Ma, 95% HPD: 11.89–20.46 Ma), Bathybatini (20.62 Ma, 95% HPD: 16.88–25.34 Ma), Lamprologini (15.27 Ma; 95% HPD: 12.23–18.49 Ma). The divergence age of the crown haplochromine H-lineage is estimated to 22.8 Ma (95% HPD: 14.40–26.32 Ma) and of the Lake Malawi radiation to 4.07 Ma (95% HDP: 2.93–5.26 Ma). In addition, we recovered a novel lineage within the Lamprologini tribe encompassing only Lamprologus of the lower and central Congo drainage with its divergence estimated to the Late Miocene or early Pliocene. Furthermore we recovered two novel mitochondrial haplotype lineages within the Haplochromini tribe: ‘Orthochromis’ indermauri and ‘Haplochormis’ vanheusdeni. Conclusions Divergence time estimates of the MRCA of several Tanganyika cichlid tribes predate the age of the extant Lake Tanganyika basin, and hence are in line with the recently formulated “Melting-Pot Tanganyika” hypothesis. The radiation of the ‘Lower Congo Lamprologus clade’ might be linked with the Pliocene origin of the modern lower Congo rapids as has been shown for other Lower Congo cichlid assemblages. Finally, the age of origin of the Lake Malawi cichlid flock agrees well with the oldest age estimate for lacustrine conditions in Lake Malawi. Electronic supplementary material The online version of this article (10.1186/s12862-019-1417-0) contains supplementary material, which is available to authorized users.
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- 2019
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17. Repeated Evolution Versus Common Ancestry: Sex Chromosome Evolution in the Haplochromine CichlidPseudocrenilabrus philander
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Andrin Riss, Alexandra Anh-Thu Weber, Astrid Böhne, Michael Rechsteiner, Bernd Egger, Walter Salzburger, and Jelena Rajkov
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Male ,0106 biological sciences ,Species complex ,Lineage (evolution) ,Population ,sex determination ,Population genetics ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,Cichlid ,Genetics ,Animals ,14. Life underwater ,species complex ,education ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,teleost fish ,0303 health sciences ,education.field_of_study ,Sex Chromosomes ,biology ,Phylogenetic tree ,Pseudocrenilabrus philander ,population genetics ,Cichlids ,Sex Determination Processes ,biology.organism_classification ,Biological Evolution ,genome sequencing ,Haplochromine ,speciation ,Evolutionary biology ,Female ,Research Article - Abstract
Why sex chromosomes turn over and remain undifferentiated in some taxa, whereas they degenerate in others, is still an area of ongoing research. The recurrent occurrence of homologous and homomorphic sex chromosomes in distantly related taxa suggests their independent evolution or continued recombination since their first emergence. Fishes display a great diversity of sex-determining systems. Here, we focus on sex chromosome evolution in haplochromines, the most species-rich lineage of cichlid fishes. We investigate sex-specific signatures in the Pseudocrenilabrus philander species complex, which belongs to a haplochromine genus found in many river systems and ichthyogeographic regions in northern, eastern, central, and southern Africa. Using whole-genome sequencing and population genetic, phylogenetic, and read-coverage analyses, we show that one population of P. philander has an XX–XY sex-determining system on LG7 with a large region of suppressed recombination. However, in a second bottlenecked population, we did not find any sign of a sex chromosome. Interestingly, LG7 also carries an XX–XY system in the phylogenetically more derived Lake Malawi haplochromine cichlids. Although the genomic regions determining sex are the same in Lake Malawi cichlids and P. philander, we did not find evidence for shared ancestry, suggesting that LG7 evolved as sex chromosome at least twice in haplochromine cichlids. Hence, our work provides further evidence for the labile nature of sex determination in fishes and supports the hypothesis that the same genomic regions can repeatedly and rapidly be recruited as sex chromosomes in more distantly related lineages.
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- 2019
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18. Testing sensory drive speciation in cichlid fish: Linking light conditions to opsin expression, opsin genotype and female mate preference
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Wright, Daniel Shane, van Eijk, Roel, Schuart, Lisa, Seehausen, Ole, Groothuis, Ton G.G., Maan, Martine E., Wright, Daniel Shane, van Eijk, Roel, Schuart, Lisa, Seehausen, Ole, Groothuis, Ton G.G., and Maan, Martine E.
- Abstract
Ecological speciation is facilitated when divergent adaptation has direct effects on selective mating. Divergent sensory adaptation could generate such direct effects, by mediating both ecological performance and mate selection. In aquatic environments, light attenuation creates distinct photic environments, generating divergent selection on visual systems. Consequently, divergent sensory drive has been implicated in the diversification of several fish species. Here, we experimentally test whether divergent visual adaptation explains the divergence of mate preferences in Haplochromine cichlids. Blue and red Pundamilia co-occur across south-eastern Lake Victoria. They inhabit different photic conditions and have distinct visual system properties. Previously, we documented that rearing fish under different light conditions influences female preference for blue versus red males. Here, we examine to what extent variation in female mate preference can be explained by variation in visual system properties, testing the causal link between visual perception and preference. We find that our experimental light manipulations influence opsin expression, suggesting a potential role for phenotypic plasticity in optimizing visual performance. However, variation in opsin expression does not explain species differences in female preference. Instead, female preference covaries with allelic variation in the long-wavelength-sensitive opsin gene (LWS), when assessed under broad-spectrum light. Taken together, our study presents evidence for environmental plasticity in opsin expression and confirms the important role of colour perception in shaping female mate preferences in Pundamilia. However, it does not constitute unequivocal evidence for the direct effects of visual adaptation on assortative mating.
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- 2020
19. Four new species of Cichlidogyrus (Platyhelminthes, Monogenea, Dactylogyridae) from Lake Victoria haplochromine cichlid fishes, with the redescription of C. bifurcatus and C. longipenis
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Maarten P.M. Vanhove, Ole Seehausen, Antoine Pariselle, Martine E. Maan, Tiziana P. Gobbin, GOBBIN, Tiziana, VANHOVE, Maarten, Seehausen, Ole, Maan, Martine, Pariselle, Antoine, and Maan group
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Gyrodactylus ,African Great Lakes ,biology ,Fauna ,Biodiversity ,Zoology ,Cichlidae ,biology.organism_classification ,Dactylogyridae ,Haplochromine ,Dactylogyridea ,Cichlid ,parasite ,Haplochromini ,Species richness ,Monogenea ,biodiversity - Abstract
African cichlids are model systems for evolutionary studies and for host-parasite interactions, because of their adaptive radiations and because they harbour many species of monogenean parasites with high host-specificity. Here, we sampled five locations in southern Lake Victoria, the youngest of the African Great Lakes. We surveyed gillinfecting monogeneans from 18 cichlid species belonging to the Lake Victoria radiation superflock and two cichlid species representing two older and distantly related lineages. We found one species of Gyrodactylus (Gyrodactylidae, Monogenea), Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011, and seven species of Cichlidogyrus (Dactylogyridae, Monogenea). Four species are herein described: Cichlidogyrus pseudodossoui n. sp., C. nyanza n. sp., C. furu n. sp., C. vetusmolendarius n. sp.. Another species is reported but not formally described (because of few specimens and morphological similarity with C. furu n. sp.). Two other species are redescribed: Cichlidogyrus bifurcatus Paperna, 1960 and C. longipenis Paperna & Thurston, 1969. Our results confirm that the monogenean fauna of Victorian littoral cichlids displays lower species richness and lower host-specificity than that of Lake Tanganyika littoral cichlids. In C. furu n. sp., hooks V are clearly longer than the other hooks, highlighting the need to re-evaluate the current classification system of haptoral configurations that considers hook pairs III-VII as rather uniform. Some morphological features of C. bifurcatus, C. longipenis and C. nyanza n. sp. suggest that these are closely related to other congeners that infect haplochromines. We also found morphological indications that representatives of Cichlidogyrus colonised Lake Victoria haplochromines or their ancestors at least twice, which is in line with the Lake Victoria superflock being colonized by two cichlid tribes (Haplochromini and Oreochromini).DisclaimerThis preprint is disclaimed for purposes of Zoological Nomenclature in accordance with the International Code of Zoological Nomenclature, Fourth Edition Articles 8.2 and 8.3 (ICZN 1999). No new names or nomenclatural changes are available from statements in this preprint.Résumé - Quatre espèces nouvelles de Cichlidogyrus (Platyhelminthes, Monogenea, Dactylogyridae) parasites d’haplochrominé (Cichlidae) du lac Victoria, avec la redescription de C. bifurcatus and C. longipenisA cause des radiations adaptatives qu’ils ont subies, les cichlidés africain sont des systèmes modèles pour étudier l’évolution, mais aussi les relations hôtes/parasites, car ils hébergent de nombreuses espèces de Monogènes parasites qui présentent une spécificité étroite vis-à-vis de leurs hôtes. Dans ce travail, nous avons échantillonné cinq localités dans le Sud du lac Victoria, le plus jeune des grands lacs d’Afrique de l’Est. Nous avons examiné les Monogènes présents sur les branchies de 18 espèces de Cichlidés appartenant à la radiation adaptative « superflock » du lac Victoria et de deux espèces représentant deux lignées anciennes et non étroitement apparentées. Nous avons trouvé une espèce de Gyrodactylus (Gyrodactylidae, Monogenea), Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011 et sept espèces de Cichlidogyrus (Dactylogyridae, Monogenea). Quatre espèces nouvelles sont décrites dans le présent travail : Cichlidogyrus pseudodossoui n. sp., C. nyanza n. sp., C. furu n. sp., C. vetusmolendarius n. sp.. Une est signalée mais non décrite formellement (trop peux d’individus recueillis, morphologiquement proche de C. furu n. sp.). Deux autres sont redécrites : Cichlidogyrus bifurcatus Paperna, 1960 and C. longipenis Paperna & Thurston, 1969. Nos résultats confirment que la faune des Monogènes des Cichlidés du lac Victoria fait preuve d’une richesse spécifique et d’une spécificité moins importante que celle du lac Tanganyika. Chez C. furu n. sp. la paire de crochet V étant nettement plus longue que les autres, il faudra reconsidérer le système de classification actuel des types de hapteurs chez les Cichlidogyrus, qui considère que tous les crochets (III à VII) ont la même taille. Quelques caractéristiques morphologiques de C. bifurcatus, C. longipenis et C. nyanza n. sp. pourraient être la preuve d’une ascendance commune avec des congénères présents chez d’autres Haplochrominés. De même, certains caractères indiqueraient que des représentants des Cichlidogyrus ont colonisé les Haplochrominés du lac Victoria, ou leurs ancêtres, au moins à deux reprises, ce qui est cohérent avec une colonisation du lac par deux lignées de cichlidés distinctes (Haplochromini and Oreochromini).
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- 2021
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20. Socio-Economic Drivers of Fish Species Consumption Preferences in Kenya’s Urban Informal Food System
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Oscar Ingasia Ayuya, Katrine Soma, and Benson Obwanga
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Nile perch ,Geography, Planning and Development ,Fish consumption ,TJ807-830 ,WASS ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,TD194-195 ,01 natural sciences ,Renewable energy sources ,Common carp ,Nile tilapia ,0502 economics and business ,Rural–urban food systems ,GE1-350 ,Socioeconomics ,Green Economy and Landuse ,0105 earth and related environmental sciences ,biology ,Environmental effects of industries and plants ,Renewable Energy, Sustainability and the Environment ,05 social sciences ,Sardine ,Informal settlement ,biology.organism_classification ,Kenya ,Lates ,Marbled lungfish ,Haplochromine ,Environmental sciences ,Oreochromis ,Kibera ,Geography ,Groene Economie en Ruimte ,Resilient food and nutrition security ,050202 agricultural economics & policy - Abstract
In an effort to contribute to resilient food and nutritional security in urban slums, a food system approach was applied to understand the key socio-economic factors driving fish species consumption in Kibera, the largest informal settlement in Africa located in Nairobi, Kenya. Data were collected from 385 randomly selected households using a structured questionnaire. A multivariate probit model was applied to estimate the relationship between the variables in order to determine the socio-economic drivers of preferences for different fish species. The results indicated that Lake Victoria sardine (Rastrineobola argentea) had the highest preference (73%) among the respondents, followed by Nile tilapia (Oreochromis niloticus) (70%) and Nile perch (Lates niloticus) (23%), respectively, with other fish species at 12%, including African catfish, marbled lungfish, common carp, fulu and tuna (Clarias gariepinus, Protopterus aethiopicus, Cyprinus carpio, Haplochromine cichlids and Thunnus sp., respectively). Large household size showed an increase in preference for the Lake Victoria sardine, while higher income influenced preference for Nile tilapia and Nile perch positively, implying that when more income is available, Nile tilapia is the preferred fish over other fish species. Increased fish prices positively influenced preference for Nile tilapia, which is explained by the willingness to pay extra for quality and origin, for instance, to avoid the cheaply cultivated Chinese fish. In the case of the Lake Victoria sardine, lower prices positively affected the preferences. Religious and cultural practices and beliefs influenced preference for species and consumption of fish. Residents who migrated from western Kenya had a higher preference for the Lake Victoria sardine, while residents born and raised in Kibera had a higher preference for Nile tilapia. Neighbourhood effects reduced the preference for consuming Nile perch. These findings provide insights into future market opportunities for specific target groups. For instance, given that small-sized fish like the Lake Victoria sardine is highly demanded, in order to increase resiliency in food and nutrition security, small-sized cheap Nile tilapia will have a large potential in the future, with ever higher demand specifically from the residents born and raised in Kibera.
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- 2021
21. Continuouscis-regulatory changes in an advantageous gene are linked with adaptive radiation in cichlid fishes
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Zongfang Wei, Wenjun Zhou, Langyu Gu, Ximin He, Li Li, Chenzheng Li, Deshou Wang, Youkui Huang, and Xiaobing Mao
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Haplochromine ,Cichlid ,Evolutionary biology ,Adaptive radiation ,Lineage (evolution) ,Single-nucleotide polymorphism ,Biology ,Adaptation ,biology.organism_classification ,Gene ,Green fluorescent protein - Abstract
Deciphering why some lineages produce spectacular radiations while others do not provides important insights into biodiversity, but the molecular basis underlying this process remains largely unknown. Here, we identified a lineage-restricted gene, which we namedlg. Combined omics analyses showed thatlgis under positive selection in the most species-rich lineage of cichlid fishes, the modern haplochromine (MH) lineage, indicating its evolutionary advantage. Using transgenic zebrafish, we functionally showed that a cichlid fish-specific upstream insertion oflgcan drive new and strong eGFP expression in tissues noted for adaptation in the MH lineage, but not in other lineages. Furthermore, the deletion of three MH-specific SNPs within this region can reconstitute weak and limited expression patterns similar to those in non-MH lineages. We thus demonstrated that a series ofcis-regulatory changes in an advantageous gene are linked with a gain of expression that is related to an astonishingly adaptive radiative lineage.
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- 2020
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22. Trophic divergence of Lake Kivu cichlid fishes along a pelagic versus littoral habitat axis
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Wilson W. L. Jere, Philippe S. Munyandamutsa, Austin Mtethiwa, and Daud Kassam
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0106 biological sciences ,kinematic transmission ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,Cichlid ,lcsh:QH540-549.5 ,Littoral zone ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Nature and Landscape Conservation ,Local adaptation ,Trophic level ,Original Research ,Morphometrics ,0303 health sciences ,Ecology ,biology ,Pelagic zone ,biology.organism_classification ,Haplochromine ,trophic morphology ,Habitat ,Lake Kivu ,lcsh:Ecology ,haplochromines ,local adaptation - Abstract
Local adaptation to the littoral and pelagic zones in two cichlid haplochromine fish species from Lake Kivu was investigated using morphometrics. Cranial variation and inferred jaw mechanics in both sexes of the two species across the two habitat types were quantified and compared. Comparisons of littoral versus pelagic populations revealed habitat‐specific differences in the shape of the feeding apparatus. Also, kinematic transmission of the anterior jaw four‐bar linkage that promotes greater jaw protrusion was higher in the pelagic zone than in the littoral zone for both species. Inferred bite force was likewise higher in pelagic zone fish. There were also sex‐specific differences in craniofacial morphology as males exhibited longer heads than females in both habitats. As has been described for other cichlids in the East African Great Lakes, local adaptation to trophic resources in the littoral and pelagic habitats characterizes these two Lake Kivu cichlids. Similar studies involving other types of the Lake Kivu fishes are recommended to test the evidence of the observed trophic patterns and their genetic basis of divergences., Comparisons of littoral versus pelagic Lake Kivu haplochromine species revealed habitat‐specific differences in the shape of the feeding apparatus.
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- 2020
23. Stomach contents and stable isotopes confirm ontogenetic diet shifts of Nile perch, Lates niloticus, in southern Lake Victoria
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I.J.M. Cornelissen, Leopold A. J. Nagelkerke, Jacobus Vijverberg, N. R. Helmsing, Johan A.J. Verreth, A. M. van den Beld, and Aquatic Ecology (AqE)
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0106 biological sciences ,Tropical lake ,Nile perch ,Zoology ,Haplochromine cichlids ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,Predation ,Aquaculture and Fisheries ,Fish-food relationships ,Dominance (ecology) ,Rastrineobola argentea ,Ecology, Evolution, Behavior and Systematics ,Invertebrate ,Ecology ,biology ,Aquacultuur en Visserij ,010604 marine biology & hydrobiology ,national ,Caridina shrimp ,biology.organism_classification ,Lates ,Shrimp ,Haplochromine ,Caridina ,WIAS - Abstract
Nile perch (Lates niloticus), a main target for Lake Victoria's fisheries, shifts its diet from invertebrates to fish during its ontogeny. We combined stomach contents with stable isotopes to study these diet shifts in Mwanza Gulf, southern Lake Victoria. During four seasons between 2009 and 2011 we collected and analysed 6697 stomachs and 516 stable isotope samples of Nile perch. Caridina shrimp and haplochromine cichlids were the major food items in Nile perch of 5–40 cm. Based on stomach contents, the shift of dominance of Caridina towards haplochromines in the diet varied from 6.7 cm length in the southern part of the gulf, to >20 cm in the northern part, possibly related to the higher abundance of Caridina in the north. In general isotope-based and stomach-content-based estimates of Nile perch diets agreed. We observed only two discrepancies: in Nile perch >20 cm, the isotope-based estimates of the contribution of haplochromines to the diet were much lower than based on stomach contents and the contribution of juvenile Nile perch to the diet were much higher in the isotope-based estimates than in the stomach based-based estimates. This discrepancy may be explained by e.g. different timespan-coverages between isotopes and stomach contents, by movements of Nile perch between the Gulf and the rest of Lake Victoria, or by the overlapping isotopic profiles of haplochromines and juvenile Nile perch. With the recent recovery of haplochromines in Lake Victoria, Nile perch appears to rely more on this prey again, as it did in the 1980s.
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- 2018
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24. Color change and pigmentation in a color polymorphic cichlid fish
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Taylor J. Piefke, Robert J. Fialkowski, Matthew R. Tryc, Gabriela M. DeOliveira, Peter D. Dijkstra, Shana E Border, and Tyler R. Funnell
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0106 biological sciences ,Social stress ,genetic structures ,Astatotilapia burtoni ,biology ,010604 marine biology & hydrobiology ,Zoology ,Aquatic Science ,biology.organism_classification ,Xanthophore ,010603 evolutionary biology ,01 natural sciences ,Haplochromine ,Pigment ,Cichlid ,Sexual selection ,visual_art ,visual_art.visual_art_medium ,Melanocortin - Abstract
In many haplochromine cichlids, body coloration is an important communication cue during social interactions. In some cichlids, individuals can change color, but we have little information about the underlying physiological mechanisms. We examined the regulation of coloration in the color polymorphic cichlid fish Astatotilapia burtoni where males are either blue or yellow. Previous studies implicated the melanocortin system, a neuroendocrine center that regulates pigmentation and the stress response, in regulating the color polymorphism in this species. We found that both blue and yellow males express a high density of yellow xanthophores. Dispersal of xanthophore pigments in both yellow and blue morphs occurred within minutes in a dose-dependent manner. Similarly, exogenous α-melanocyte stimulating hormone (α-MSH, a melanocortin hormone) increased yellowness of the body in a dose-independent fashion. We observed many color changes in males housed in social communities with the proportion of yellow males increasing over the 2-week experimental period. However, color phenotype or color change was not influenced by experimental alteration of the stability of the social hierarchy. The effects of α-MSH suggest that the melanocortin system contributes to the polymorphism in coloration in A. burtoni but the role of social interactions and social stress in regulating color remains unclear.
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- 2018
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25. Grasping ecological opportunities: not one but five paedophagous species of Haplochromis (Teleostei: Cichlidae) in the Lake Edward system
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Nathan Vranken, Jos Snoeks, and Maarten Van Steenberge
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0106 biological sciences ,Ecological niche ,Teleostei ,biology ,Ecology ,010604 marine biology & hydrobiology ,Haplochromis taurinus ,Aquatic Science ,Mouthbrooder ,biology.organism_classification ,Haplochromis ,010603 evolutionary biology ,01 natural sciences ,Haplochromine ,Paedophagy ,Trophic level - Abstract
The Lake Edward system in Eastern Central Africa, including Lakes Edward and George and their associated rivers, is home to a species assemblage of endemic haplochromine cichlids. Currently, 36 of these species have been formally described, while it is estimated that the system may harbour a total of 60 species. Species flocks of haplochromine cichlids are morphologically and ecologically very diverse and have radiated into many specialised trophic niches. Paedophagy is the feeding on eggs and larvae. In Haplochromis, most paedophages steal fry and eggs from the buccal cavities of mouthbrooding female cichlids. Hitherto, one formally described species with this diet is known from the Lake Edward system: Haplochromis taurinus. We performed a morphometrical revision of all species of Haplochromis from this system with a morphology that suggests a paedophagous diet: long oral jaws set with small teeth. Sixty-eight specimens were studied by taking 28 measurements and 20 counts and by performing stomach content observations. We discovered that H. paradoxus also had a paedophagous diet. Our analyses further revealed the presence of three new species: H. gracilifur sp. nov., H. molossus sp. nov., and H. relictidens sp. nov. All five of these species were described or redescribed.
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- 2018
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26. Guilty as charged: Nile perch was the cause of the haplochromine decline in Lake Victoria
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Brian E. Marshall
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0106 biological sciences ,Biomass (ecology) ,education.field_of_study ,biology ,010604 marine biology & hydrobiology ,Nile perch ,Population ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Lates ,Predation ,Fishery ,Haplochromine ,Food chain ,education ,Eutrophication ,Ecology, Evolution, Behavior and Systematics - Abstract
Debate on the contribution of Nile perch (Lates niloticus) to the demise of Lake Victoria’s 500+ endemic haplochromine cichlids centers around the “top-down” and “bottom-up” hypotheses. The former suggests Nile perch destroyed the haplochromines, causing the disruption of food chains and nutrient cycling and so initiating the accelerated eutrophication of the lake. The latter proposes that haplochromines suppressed Nile perch by preying on its eggs and fry or competing with juveniles for food. A recent paper argued that accelerated eutrophication caused by a climatic event led to their collapse, allowing Nile perch to explode. However, the Nile perch population grew before haplochromines decreased, and they only collapsed once Nile perch biomass exceeded theirs. The chronology indicates that accelerated eutrophication of the lake followed rather than preceded the haplochromine collapse, suggesting that eutrophication was not its cause. A size-selective predation model developed to support the bottom-up hypothesis is discussed in light of existing data, but does not support the bottom-up hypothesis. It was concluded that the top-down model better fits the data and conforms to the law of parsimony.
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- 2018
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27. Early developmental and allometric patterns in the electric yellow cichlidLabidochromis caeruleus
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Claudius F. Kratochwil, Axel Meyer, Hamed Mousavi-Sabet, Maryam Saemi-Komsari, Masoud Sattari, and Soheil Eagderi
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0301 basic medicine ,Hatching ,Ontogeny ,Zoology ,Aquatic Science ,Mouthbrooder ,Biology ,biology.organism_classification ,Haplochromine ,03 medical and health sciences ,030104 developmental biology ,Cichlid ,Adaptive radiation ,Allometry ,human activities ,Labidochromis caeruleus ,Ecology, Evolution, Behavior and Systematics - Abstract
The electric yellow cichlid Labidochromis caeruleus is a mouth-brooding haplochromine cichlid from Lake Malawi and one of the most popular cichlids in the ornamental fish industry. To investigate the early development of L. caeruleus from hatching until the juvenile stage, we studied its morphological development and allometric growth patterns. In newly-hatched larvae, most organs and body parts were not yet differentiated and continued to develop until 15 days post hatching (dph). The yolk sac was depleted at 13 dph. There was allometric growth, primarily in the anterior and posterior regions of the body, and inflection points when trajectories of allometric growth changed. Head and tail growth was prioritized, suggesting that body parts linked to feeding and swimming behaviour mature earlier than the rest of the body. Additionally, growth patterns revealed that development of organs related to vital functions such as branchial respiration, sensation, exogenous feeding and swimming was prioritized. Comparisons with other African and Neotropical cichlids revealed differences in ontogenetic processes and allometric growth along the anterior-posterior axis as well as variation in developmental timing. These results indicate how early morphological development and ontogenic processes might respond to the distinctive parental care observed in mouth-brooding cichlids.
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- 2018
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28. Variation of anal fin egg-spots along an environmental gradient in a haplochromine cichlid fish
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Walter Salzburger, Fabio Cortesi, Olivia Roth, Fabrizia Ronco, Bernd Egger, and Anya Theis
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0106 biological sciences ,0301 basic medicine ,Natural selection ,Astatotilapia burtoni ,biology ,Ecology ,Fish fin ,Zoology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Intraspecific competition ,Haplochromine ,03 medical and health sciences ,030104 developmental biology ,Cichlid ,Sexual selection ,Genetics ,Adaptation ,General Agricultural and Biological Sciences ,Ecology, Evolution, Behavior and Systematics - Abstract
Male secondary sexual traits are targets of inter- and/or intrasexual selection, but can vary due to a correlation with life-history traits or as by-product of adaptation to distinct environments. Trade-offs contributing to this variation may comprise conspicuousness towards conspecifics versus inconspicuousness towards predators, or between allocating resources into coloration versus the immune system. Here, we examine variation in expression of a carotenoid-based visual signal, anal-fin egg-spots, along a replicate environmental gradient in the haplochromine cichlid fish Astatotilapia burtoni. We quantified egg-spot number, area, and coloration; applied visual models to estimate the trait's conspicuousness when perceived against the surrounding tissue under natural conditions; and used the lymphocyte ratio as a measure for immune activity. We find that (i) males possess larger and more conspicuous egg-spots than females, which is likely explained by their function in sexual selection; (ii) riverine fish generally feature fewer but larger and/or more intensively colored egg-spots, which is probably to maintain signal efficiency in intraspecific interactions in long-wavelength shifted riverine light conditions; and (iii) egg-spot number and relative area correlate with immune defense, suggesting a trade-off in the allocation of carotenoids. Taken together, haplochromine egg-spots feature the potential to adapt to the respective underwater light environment, and are traded-off with investment into the immune system
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- 2017
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29. Fish species and trophic diversity of haplochromine cichlids in the Kyoga satellite lakes (Uganda).
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Mbabazi, Dismas, Ogutu-Ohwayo, R., Wandera, S. B., and Kiziito, Y.
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FISHES , *BIODIVERSITY , *INSECTIVORES (Mammals) , *NILE perch , *NATURE conservation - Abstract
Prior to the 1980s, lakes Kyoga and Victoria previously supported an exceptionally diverse haplochromine fish fauna comprising at least 11 trophic groups. The species and trophic diversity in these lakes decreased when the introduced Nile perch depleted haplochromine stocks. From December 1996 to October 1998, we studied species and trophic diversity of haplochromine fishes in six satellite lakes without Nile perch in the Kyoga basin and compared them with the Kyoga main lake against historical data from Lake Victoria where Nile perch were introduced. Forty-one species were found in the study area, of which, the Kyoga satellite lakes contributed 37 species in comparison to only 14 from the Kyoga main lake. Analysis of trophic diversity based on 24 species that contained food material revealed seven haplochromine trophic groups (insectivores, peadophages, piscivores, algal eaters, higher plant eaters, molluscivores and detritivores) in the Kyoga satellite lakes in comparison to two trophic groups (insectivores and molluscivores) in the Kyoga main lake. Many of the species and trophic groups of haplochromines depleted by the introduced Nile perch in lakes Kyoga and Victoria still survive in the Kyoga satellite lakes. This is attributed to the absence of Nile perch in those lakes. Nile perch has been prevented from spreading into the satellite lakes by swamp vegetation that separate them from the main lakes. If these swamps prevent Nile perch from spreading into the lakes, it is possible to conserve fish species, especially haplochromines, which are threatened by introduction of Nile perch in the main lakes. [ABSTRACT FROM AUTHOR]
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- 2004
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30. Appetite regulating genes may contribute to herbivory versus carnivory trophic divergence in haplochromine cichlids
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Ehsan Pashay Ahi, Anna Duenser, Wolfgang Gessl, Pooja Singh, Christian Sturmbauer, and Organismal and Evolutionary Biology Research Programme
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0106 biological sciences ,FOOD-INTAKE ,Anorexigenic ,TILAPIA OREOCHROMIS-NILOTICUS ,lcsh:Medicine ,Freshwater Biology ,01 natural sciences ,Evolutionsbiologi ,0302 clinical medicine ,Adaptive radiation ,Reference genes ,Appetite regulation ,East African Lakes ,ORANGE-SPOTTED GROUPER ,TISSUE DISTRIBUTION ,Trophic level ,media_common ,0303 health sciences ,General Neuroscience ,Brain ,General Medicine ,Cichlids ,TRANSCRIPT CART ,Evolutionary Studies ,NEUROPEPTIDE-Y ,Trophic specialization ,1181 Ecology, evolutionary biology ,General Agricultural and Biological Sciences ,MECHANICAL STRAIN ,medicine.drug ,QUANTITATIVE RT-PCR ,media_common.quotation_subject ,Foraging ,FEEDING-BEHAVIOR ,Zoology ,Orexigenic ,Biology ,010603 evolutionary biology ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Cichlid ,medicine ,Genetics ,Molecular Biology ,030304 developmental biology ,Evolutionary Biology ,lcsh:R ,Appetite ,INDUCED PHENOTYPIC PLASTICITY ,biology.organism_classification ,Haplochromine ,Larval development ,Gene expression ,human activities ,030217 neurology & neurosurgery ,Developmental Biology - Abstract
Feeding is a complex behaviour comprised of satiety control, foraging, ingestion and subsequent digestion. Cichlids from the East African Great Lakes are renowned for their diverse trophic specializations, largely predicated on highly variable jaw morphologies. Thus, most research has focused on dissecting the genetic, morphological and regulatory basis of jaw and teeth development in these species. Here for the first time we explore another aspect of feeding, the regulation of appetite related genes that are expressed in the brain and control satiety in cichlid fishes. Using qPCR analysis, we first validate stably expressed reference genes in the brain of six haplochromine cichlid species at the end of larval development prior to foraging. We next evaluate the expression of 16 appetite related genes in herbivorous and carnivorous species from the parallel radiations of Lake Tanganyika, Malawi and Victoria. Interestingly, we find increased expression of two anorexigenic genes, cart and npy2r, in the brain of carnivorous species in all the lakes. This supports the notion that herbivory compared to carnivory requires stronger appetite stimulation in order to feed larger quantity of food and to compensate for the relatively poorer nutritional quality of a plant- and algae-based diet. Our study contributes to the limited body of knowledge on the neurological circuitry that controls feeding transitions and adaptations and in cichlids and other teleosts.
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- 2019
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31. Testing sensory drive speciation in cichlid fish: Linking light conditions to opsin expression, opsin genotype and female mate preference
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Roel van Eijk, Lisa Schuart, Ton G. G. Groothuis, Daniel Shane Wright, Ole Seehausen, Martine E. Maan, Maan group, Neurobiology, Evolutionary Genetics, Development & Behaviour, and Groothuis lab
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0106 biological sciences ,0301 basic medicine ,Male ,genetic structures ,Adaptation, Biological ,01 natural sciences ,phenotypic plasticity ,SEXUAL SELECTION ,LOCAL ADAPTATION ,Haplochromine ,Pundamilia ,Terrestrische ecologie en natuurbeheer ,ecological speciation ,PLASTICITY ,LWS ,GENE-EXPRESSION ,LAKE VICTORIA CICHLIDS ,biology ,Cichlids ,Research Papers ,Mate choice ,Sexual selection ,Female ,Color Perception ,BLUEFIN KILLIFISH ,Research Paper ,GASTEROSTEUS ,Genetic Speciation ,010603 evolutionary biology ,Ecological speciation ,03 medical and health sciences ,Cichlid ,NUPTIAL COLORATION ,Terrestrial Ecology and Nature Conservation ,ASSORTATIVE MATING PREFERENCES ,Animals ,Ecology, Evolution, Behavior and Systematics ,ENVIRONMENT ,Phenotypic plasticity ,Color Vision ,Opsins ,Assortative mating ,Mating Preference, Animal ,biology.organism_classification ,visual pigment ,030104 developmental biology ,Evolutionary biology ,570 Life sciences ,Adaptation - Abstract
Ecological speciation is facilitated when divergent adaptation has direct effects on selective mating. Divergent sensory adaptation could generate such direct effects, by mediating both ecological performance and mate selection. In aquatic environments, light attenuation creates distinct photic environments, generating divergent selection on visual systems. Consequently, divergent sensory drive has been implicated in the diversification of several fish species. Here, we experimentally test whether divergent visual adaptation explains the divergence of mate preferences in Haplochromine cichlids. Blue and red Pundamilia co‐occur across south‐eastern Lake Victoria. They inhabit different photic conditions and have distinct visual system properties. Previously, we documented that rearing fish under different light conditions influences female preference for blue versus red males. Here, we examine to what extent variation in female mate preference can be explained by variation in visual system properties, testing the causal link between visual perception and preference. We find that our experimental light manipulations influence opsin expression, suggesting a potential role for phenotypic plasticity in optimizing visual performance. However, variation in opsin expression does not explain species differences in female preference. Instead, female preference covaries with allelic variation in the long‐wavelength‐sensitive opsin gene (LWS), when assessed under broad‐spectrum light. Taken together, our study presents evidence for environmental plasticity in opsin expression and confirms the important role of colour perception in shaping female mate preferences in Pundamilia. However, it does not constitute unequivocal evidence for the direct effects of visual adaptation on assortative mating., Pundamilia cichlids exhibit light‐induced opsin expression plasticity, which correlates with female mate preference, but does not explain species differences in preference. Instead, female preference covaries with allelic variation in the LWS opsin in broad‐spectrum light, confirming the important role of colour perception in shaping Pundamilia mate preferences.
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- 2019
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32. Chromosome-scale assemblies reveal the structural evolution of African cichlid genomes
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Rajesh Joshi, Karen L. Carleton, William J Gammerdinger, Sigbjørn Lien, Thomas D. Kocher, Emily C. Moore, Matthew A. Conte, Reade B. Roberts, and Sri Pratima Nandamuri
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0106 biological sciences ,Genetic Linkage ,genome rearrangements ,Lineage (evolution) ,Karyotype ,chromosome evolution ,Sequence assembly ,Genomics ,Health Informatics ,comparative genomics ,Biology ,010603 evolutionary biology ,01 natural sciences ,Genome ,African cichlids ,Evolution, Molecular ,Structural variation ,inversion ,03 medical and health sciences ,Cichlid ,Animals ,Repetitive Sequences, Nucleic Acid ,030304 developmental biology ,Recombination, Genetic ,Comparative genomics ,0303 health sciences ,Research ,Chromosome Mapping ,Computational Biology ,Molecular Sequence Annotation ,Cichlids ,biology.organism_classification ,Diploidy ,recombination ,Computer Science Applications ,Haplochromine ,Evolutionary biology ,genetic maps ,DNA Transposable Elements ,genome assembly ,transposable elements ,Adaptation ,human activities ,010606 plant biology & botany - Abstract
BackgroundAfrican cichlid fishes are well known for their rapid radiations and are a model system for studying evolutionary processes. Here we compare multiple, high-quality, chromosome-scale genome assemblies to understand the genetic mechanisms underlying cichlid diversification and study how genome structure evolves in rapidly radiating lineages.ResultsWe re-anchored our recent assembly of the Nile tilapia (Oreochromis niloticus) genome using a new high-density genetic map. We developed a newde novogenome assembly of the Lake Malawi cichlid,Metriaclima zebra, using high-coverage PacBio sequencing, and anchored contigs to linkage groups (LGs) using four different genetic maps. These new anchored assemblies allow the first chromosome-scale comparisons of African cichlid genomes.Large intra-chromosomal structural differences (~2-28Mbp) among species are common, while inter-chromosomal differences are rare (< 10Mbp total). Placement of the centromeres within chromosome-scale assemblies identifies large structural differences that explain many of the karyotype differences among species. Structural differences are also associated with unique patterns of recombination on sex chromosomes. Structural differences on LG9, LG11 and LG20 are associated with reductions in recombination, indicative of inversions between the rock- and sand-dwelling clades of Lake Malawi cichlids.M. zebrahas a larger number of recent transposable element (TE) insertions compared toO. niloticus, suggesting that several TE families have a higher rate of insertion in the haplochromine cichlid lineage.ConclusionThis study identifies novel structural variation among East African cichlid genomes and provides a new set of genomic resources to support research on the mechanisms driving cichlid adaptation and speciation.
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- 2019
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33. Ecosystem Modifications (1956-2014) in Lake Victoria (East Africa): A Review
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Moshe Gophen
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Haplochromine ,Environmental Engineering ,Predatory fish ,Geography ,biology ,Ecology ,Nile perch ,Species diversity ,Dominance (ecology) ,Ecosystem ,Hypolimnion ,biology.organism_classification ,Lates - Abstract
A brief historical (1956-2014) review of the Lake Victoria ecological development is presented. The Lake Victoria ecosystem structure was thoroughly modified after the invasion of the predator fish Lates niloticus (Nile perch). The relative capacity and functional activity of the food-web compartments was quantitative and qualitative altered. The trophic status of Lake Victoria ecosystem was shifted toward eutrophication : phytoplankton species composition and densities were modified, fish assemblages were converted from about 400 Haplochromine species diversity to large body predator , Nile perch dominance. Consequently , the fishery was changed accompanied by Socio-Economic consequences. The thermal structure trait shifted towards enhancement of anoxia and Hypolimnetic volume extension.
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- 2019
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34. Geographic variation in opsin expression does not align with opsin genotype in Lake Victoria cichlid populations
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Ole Seehausen, Roel van Eijk, Daniel Shane Wright, Roy Meijer, Martine E. Maan, Wicher Vos, Maan group, and Evolutionary Genetics, Development & Behaviour
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0106 biological sciences ,Opsin ,genetic structures ,Population ,TUNING SPECTRAL SENSITIVITY ,sensory drive ,010603 evolutionary biology ,01 natural sciences ,SEXUAL SELECTION ,Ecological speciation ,03 medical and health sciences ,FISH ,Cichlid ,lcsh:QH540-549.5 ,haplochromine ,ecological speciation ,14. Life underwater ,INTERSPECIFIC VARIATION ,LWS ,education ,SPECIATION ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Nature and Landscape Conservation ,GENE-EXPRESSION ,Original Research ,0303 health sciences ,education.field_of_study ,Ecology ,biology ,Pundamilia ,biology.organism_classification ,VISUAL PIGMENTS ,eye diseases ,COLOR-VISION ,Haplochromine ,Sympatric speciation ,Evolutionary biology ,lcsh:Ecology ,Adaptation ,BLUEFIN KILLIFISH - Abstract
Sensory adaptation to the local environment can contribute to speciation. Aquatic environments are well suited for studying this process: The natural attenuation of light through water results in heterogeneous light environments, to which vision-dependent species must adapt for communication and survival. Here, we study visual adaptation in sympatric Pundamilia cichlids from southeastern Lake Victoria. Species with blue or red male nuptial coloration co-occur at many rocky islands but tend to be depth-differentiated, entailing different visual habitats, more strongly at some islands than others. Divergent visual adaptation to these environments has been implicated as a major factor in the divergence of P. pundamilia and P. nyererei, as they show consistent differentiation in the long-wavelength-sensitive visual pigment gene sequence (LWS opsin). In addition to sequence variation, variation in the opsin gene expression levels may contribute to visual adaptation. We characterized opsin gene expression and LWS genotype across Pundamilia populations inhabiting turbid and clear waters, to examine how different mechanisms of visual tuning contribute to visual adaptation. As predicted, the short-wavelength-sensitive opsin (SWS2b) was expressed exclusively in a population from clear water. Contrary to prediction however, expression levels of the other opsins were species- and island-dependent and did not align with species differences in LWS genotype. Specifically, in two locations with turbid water, the shallow-water dwelling blue species expressed more LWS and less RH2A than the deeper-dwelling red species, while the opposite pattern occurred in the two locations with clear water. Visual modeling suggests that the observed distribution of opsin expression profiles and LWS genotypes does not maximize visual performance, implying the involvement of additional visual tuning mechanisms and/or incomplete adaptation.OPEN RESEARCH BADGE: This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://hdl.handle.net/10411/I1IUUQ.
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- 2019
35. Recent sympatric speciation involving habitat-associated nuptial colour polymorphism in a crater lake cichlid
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Lauren J. Chapman, Colin A. Chapman, Marcel P. Haesler, Mélissa Lemoine, Salome Mwaiko, Ole Seehausen, Marta Barluenga, Kay Lucek, Swiss National Science Foundation, and Wildlife Conservation Society
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0106 biological sciences ,Sympatry ,010604 marine biology & hydrobiology ,Allopatric speciation ,Zoology ,Reproductive isolation ,Crater lakes ,15. Life on land ,Aquatic Science ,Biology ,Cichlidae ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Ecological speciation ,Haplochromine ,Sexual selection ,Sympatric speciation ,Cichlid ,Lake Victoria region ,Crater lake ,570 Life sciences ,biology ,Microsatellites - Abstract
Even though the idea that modes of speciation other than allopatric speciation are possible in nature is now widespread, compelling examples of ecological speciation in sympatry remain rare. We studied an undescribed radiation of haplochromine cichlids in a young crater lake in western Uganda, and in the small river that is nearby but has currently no known surface connection to the lake. We describe two different modes of speciation that occurred in this cichlid lineage within the past 1,500–10,000 years. Not constrained by gene flow, allopatric divergence between river and lake cichlids affects many different morphological traits as well as nuptial colouration—muted in the river, but intensified and polymorphic in lake cichlids—and neutral genetic differentiation. More surprisingly, we demonstrate a case for sympatric speciation within the small lake that is associated with dramatic differences in male breeding colouration (yellow with bright red-chest versus bright blue) and subtle differences in microhabitat, feeding regime and morphology. Reproductive isolation by assortative mating is suggested by significant differentiation between yellow and blue males in neutral markers of gene flow despite complete sympatry. We hypothesize speciation is mediated by divergent selection on sexual signalling between microhabitats., The genetic lab work was supported by Swiss National Science Foundation Grants 3100A0-118293/1 and 31003A_163338 to OS. Field work conducted by LJC was supported by Funding for this research was provided from the National Science Foundation and the Wildlife Conservation Society.
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- 2019
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36. Stable isotope evidence from formalin–ethanol-preserved specimens indicates dietary shifts and increasing diet overlap in Lake Victoria cichlids
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Frans Witte, Jacco C. van Rijssel, Amanda E. Poste, Mary A. Kishe-Machumu, and Robert E. Hecky
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0106 biological sciences ,biology ,δ13C ,Stable isotope ratio ,Ecology ,010604 marine biology & hydrobiology ,δ15N ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Predation ,Haplochromine ,Cichlid ,Ecosystem ,sense organs ,skin and connective tissue diseases ,Trophic level - Abstract
Stable isotopes are increasingly being used to infer past and present trophic interactions in light of environmental changes. The Lake Victoria haplochromine cichlids have experienced severe environmental changes in the past decades that, amongst others, resulted in a dietary shift towards larger prey. We investigated how the changed environment and diet of the haplochromines influenced stable isotope values of formalin-then-ethanol-preserved cichlid specimens, and then investigated how these values differed among species before (1977–1982) and after substantial environmental changes (2005–2007). We found a small preservation effect on both δ13C and δ15N values, and significant differences in isotope values among haplochromine species collected before the environmental changes. In contrast, there was a remarkable similarity in δ13C and δ15N values among species collected from the contemporary ecosystem and two out three species showed significantly different stable isotope values compared to species of the historic ecosystem. In addition, we found a putative isotopic gradient effect along our 5-km-long research transect indicating that the studied demersal species are more stenotopic than previously thought. The environmental changes have resulted in dietary change and overlap of the haplochromines which provides insight into the trophic plasticity of these species, which are often considered trophic specialists.
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- 2016
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37. The occurrence of an Eastern African haplochromine cichlid in the Ituri River (Aruwimi, Congo basin): adaptive divergence in an introduced species?
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Eva Decru, Jos Snoeks, and Emmanuel Vreven
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0106 biological sciences ,education.field_of_study ,biology ,Ecology ,Population ,010607 zoology ,Introduced species ,Aquatic Science ,Haplochromis ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Haplochromine ,Haplochromis aeneocolor ,Habitat ,Genus ,Cichlid ,education - Abstract
Recently, specimens belonging to the genus ‘Haplochromis’ have been found in the Ituri River (Congo basin). They clearly do not belong to any of the species known from the Congo basin, but strongly resemble ‘H’. aeneocolor from the Lake Edward/George system. We examined whether this population represents a new species or is conspecific with ‘H’. aeneocolor. A morphological comparative study was executed based on 11 counts and 23 measurements on 64 specimens. The results revealed the Ituri specimens to differ from the types of ‘H’. aeneocolor in snout length, premaxillary pedicel length and eye diameter. Since these few differences are correlated, and head morphology is known to be subject to adaptive responses in haplochromine cichlids, they were considered the result of morphological adaptation to a riverine habitat rather than an indication of heterospecificity. Probably, ‘H’. aeneocolor has accidentally been introduced into the Ituri region together with tilapias used in aquaculture, and has subsequently established a stable population in a riverine environment. As fish introductions can have a severe impact on aquatic ecosystems, improving our knowledge as well as a good management of aquacultural activities is essential.
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- 2016
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38. Changing ecology of Lake Victoria cichlids and their environment: evidence from C13 and N15 analyses
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Frans Witte, Mary A. Kishe-Machumu, Jacobus Cornelis van Rijssel, and Robert E. Hecky
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0106 biological sciences ,Ecology ,010604 marine biology & hydrobiology ,Species diversity ,δ15N ,Aquatic Science ,Biology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Freshwater ecosystem ,Haplochromine ,Habitat ,Cichlid ,570 Life sciences ,biology ,Eutrophication ,Invertebrate - Abstract
Eutrophication is an increasing global threat to freshwater ecosystems. East Africa’s Lake Victoria has suffered from severe eutrophication in the past decades which is partly responsible for the dramatic decline in haplochromine cichlid species diversity. However, some zooplanktivorous and detritivorous haplochromine species recovered and shifted their diet towards macro invertebrates and fish. We used four formalin preserved cichlid species caught over the past 35 years to investigate whether stable isotopes of these fish are reflecting the dietary changes, habitat differences and if these isotopes can be used as indicators of eutrophication. We found that d15N signatures mainly reflected dietary shifts to larger prey in all four haplochromine species. Shifts in d13C signatures likely represented habitat differences and dietary changes. In addition, a shift to remarkably heavy d13C signatures in 2011 was found for all four species which might infer increased primary production and thus eutrophication although more research is needed to confirm this hypothesis. The observed temporal changes confirm previous findings that preserved specimens can be used to trace historical changes in fish ecology and the aquatic environment. This highlights the need for continued sampling as this information could be of essence for reconstructing and predicting the effects of environmental changes.
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- 2016
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39. The Nile perch invasion in Lake Victoria: cause or consequence of the haplochromine decline?
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Sally Macintyre, Thomas B. Bridgeman, Michael J. Plank, Paul A.M. van Zwieten, Robert E. Hecky, Gregory M. Silsbe, Ole Seehausen, and Jeppe Kolding
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0106 biological sciences ,biology ,Aquacultuur en Visserij ,010604 marine biology & hydrobiology ,Nile perch ,Limnology ,Introduced species ,Aquatic animal ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Lates ,Invasive species ,Predation ,Haplochromine ,Fishery ,Aquaculture and Fisheries ,WIAS ,Life Science ,570 Life sciences ,Ecology, Evolution, Behavior and Systematics - Abstract
We review alternative hypotheses and associated mechanisms to explain Lake Victoria’s Nile perch (Lates niloticus) takeover and concurrent reduction in haplochromines through a (re)analysis of long-term climate, limnological, and stock observations in comparison with size-spectrum model predictions of co-existence, extinction, and demographic change. The empirical observations are in agreement with the outcomes of the model containing two interacting species with life histories matching Nile perch and a generalized haplochromine. The dynamic interactions may have depended on size-related differences in early juvenile mortality: mouth-brooding haplochromines escape predation mortality in early life stages, unlike Nile perch, which have miniscule planktonic eggs and larvae. In our model, predation on the latter by planktivorous haplochromine fry acts as a stabilizing factor for co-existence, but external mortality on the haplochromines would disrupt this balance in favor of Nile perch. To explain the observed switch, mortality on haplochromines would need to be much higher than the fishing mortality that can be realistically reconstructed from observations. Abrupt concomitant changes in algal and zooplankton composition, decreased water column transparency, and widespread hypoxia from increased eutrophication most likely caused haplochromine biomass decline. We hypothesize that the shift to Nile perch was a consequence of an externally caused, climate-triggered decrease in haplochromine biomass and associated recruitment failure rather than a direct cause of the introduction.
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- 2016
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40. Female Maylandia zebra prefer victorious males
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Rebecca Jordan, C. M. Tarsiewicz, and David Thomas Mellor
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Male ,Competitive Behavior ,bepress|Life Sciences|Ecology and Evolutionary Biology|Terrestrial and Aquatic Ecology ,biology ,Ecology ,Reproduction ,Zoology ,bepress|Life Sciences|Animal Sciences ,Cichlids ,Aquatic Science ,Mating Preference, Animal ,biology.organism_classification ,bepress|Life Sciences|Ecology and Evolutionary Biology ,Preference ,Haplochromine ,Aggression ,Maylandia zebra ,bepress|Life Sciences ,bepress|Life Sciences|Animal Sciences|Zoology ,Sexual selection ,Animals ,Female ,bepress|Life Sciences|Ecology and Evolutionary Biology|Behavior and Ethology ,human activities ,Ecology, Evolution, Behavior and Systematics - Abstract
Females of a widespread species of the rock-dwelling haplochromine cichlids of Lake Malawi, Maylandia zebra, show preference for males that successfully evict intruding males from their territory. This behaviour, experimentally induced by the investigators in a laboratory setting, was also preferred over males that were not permitted to interact with any other individual.
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- 2018
41. Visual adaptation and microhabitat choice in Lake Victoria cichlid fish
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Martine E. Maan, Ton G. G. Groothuis, Ole Seehausen, Corina van Kammen, Daniel Mameri, Groothuis lab, and Maan group
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0106 biological sciences ,habitat choice ,Visual perception ,genetic structures ,media_common.quotation_subject ,Population ,microhabitat ,sensory drive ,010603 evolutionary biology ,01 natural sciences ,Ecological speciation ,03 medical and health sciences ,Cichlid ,haplochromine ,ecological speciation ,14. Life underwater ,Mating ,lcsh:Science ,education ,030304 developmental biology ,media_common ,fish ,0303 health sciences ,education.field_of_study ,Multidisciplinary ,colour vision ,biology ,Ecology ,Pundamilia ,Biology (Whole Organism) ,Reproductive isolation ,biology.organism_classification ,Haplochromine ,Speciation ,Habitat ,570 Life sciences ,lcsh:Q ,Research Article - Abstract
Electronic supplementary material is available online at https://dx.doi.org/10.6084/m9.figshare. c.4440182 When different genotypes choose different habitats to better match their phenotypes, genetic differentiation within a population may be promoted. Mating within those habitats may subsequently contribute to reproductive isolation. In cichlid fish, visual adaptation to alternative visual environments is hypothesized to contribute to speciation. Here, we investigated whether variation in visual sensitivity causes different visual habitat preferences, using two closely related cichlid species that occur at different but overlapping water depths in Lake Victoria and that differ in visual perception (Pundamilia spp.). In addition to species differences, we explored potential effects of visual plasticity, by rearing fish in two different light conditions: broad-spectrum (mimicking shallow water) and red-shifted (mimicking deeper waters). Contrary to expectations, fish did not prefer the light environment that mimicked their typical natural habitat. Instead, we found an overall preference for the broad-spectrum environment. We also found a transient influence of the rearing condition, indicating that the assessment of microhabitat preference requires repeated testing to control for familiarity effects. Together, our results show that cichlid fish exert visual habitat preference but do not support straightforward visual habitat matching info:eu-repo/semantics/publishedVersion
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- 2018
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42. Maternal mRNA input of growth and stress-response-related genes in cichlids in relation to egg size and trophic specialization
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Laurène Alicia Lecaudey, Pooja Singh, Wolfgang Gessl, Christian Sturmbauer, and Ehsan Pashay Ahi
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0301 basic medicine ,Eggs ,lcsh:Evolution ,Zoology ,Haplochromine cichlids ,Mouthbrooder ,Zoologi ,Evolutionsbiologi ,03 medical and health sciences ,Abundance (ecology) ,Cichlid ,Adaptive radiation ,lcsh:QH359-425 ,Genetics ,Ecology, Evolution, Behavior and Systematics ,Trophic level ,Evolutionary Biology ,biology ,Research ,Maternal effect ,Maternal mRNA ,biology.organism_classification ,Haplochromine ,030104 developmental biology ,East African lakes ,Trophic specialization ,Adaptation ,Developmental Biology - Abstract
Background Egg size represents an important form of maternal effect determined by a complex interplay of long-term adaptation and short-term plasticity balancing egg size with brood size. Haplochromine cichlids are maternal mouthbrooders showing differential parental investment in different species, manifested in great variation in egg size, brood size and duration of maternal care. Little is known about maternally determined molecular characters of eggs in fishes and their relation to egg size and trophic specialization. Here we investigate maternal mRNA inputs of selected growth- and stress-related genes in eggs of mouthbrooding cichlid fishes adapted to different trophic niches from Lake Tanganyika, Lake Malawi, Lake Victoria and compare them to their riverine allies. Results We first identified two reference genes, atf7ip and mid1ip1, to be suitable for cross-species quantification of mRNA abundance via qRT-PCR in the cichlid eggs. Using these reference genes, we found substantial variation in maternal mRNA input for a set of candidate genes related to growth and stress response across species and lakes. We observed negative correlation of mRNA abundance between two of growth hormone receptor paralogs (ghr1 and ghr2) across all haplochromine cichlid species which also differentiate the species in the two younger lakes, Malawi and Lake Victoria, from those in Lake Tanganyika and ancestral riverine species. Furthermore, we found correlations between egg size and maternal mRNA abundance of two growth-related genes igf2 and ghr2 across the haplochromine cichlids as well as distinct clustering of the species based on their trophic specialization using maternal mRNA abundance of five genes (ghr1, ghr2, igf2, gr and sgk1). Conclusions These findings indicate that variations in egg size in closely related cichlid species can be linked to differences in maternal RNA deposition of key growth-related genes. In addition, the cichlid species with contrasting trophic specialization deposit different levels of maternal mRNAs in their eggs for particular growth-related genes; however, it is unclear whether such differences contribute to differential morphogenesis at later stages of development. Our results provide first insights into this aspect of gene activation, as a basis for future studies targeting their role during ecomorphological specialization and adaptive radiation. Electronic supplementary material The online version of this article (10.1186/s13227-018-0112-3) contains supplementary material, which is available to authorized users.
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- 2018
43. The onset of ecological diversification 50 years after colonization of a crater lake by haplochromine cichlid fishes
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Benjamin P. Ngatunga, Florian Nicolo Moser, Salome Mwaiko, Jacco C. van Rijssel, Ole Seehausen, and Joana I. Meier
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0106 biological sciences ,0301 basic medicine ,Ecological selection ,Population ,Niche expansion ,Biology ,010603 evolutionary biology ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Onderzoeksformatie ,Fitness surfaces ,Cichlid fish ,Cichlid ,Adaptive radiation ,Crater lake ,14. Life underwater ,education ,General Environmental Science ,Incipient speciation ,education.field_of_study ,General Immunology and Microbiology ,Disruptive selection ,Ecology ,General Medicine ,biology.organism_classification ,Haplochromine ,030104 developmental biology ,General Agricultural and Biological Sciences ,human activities - Abstract
Adaptive radiation research typically relies on the study of evolution in retrospective, leaving the predictive value of the concept hard to evaluate. Several radiations, including the cichlid fishes in the East African Great Lakes, have been studied extensively, yet no study has investigated the onset of the intraspecific processes of niche expansion and differentiation shortly after colonization of an adaptive zone by cichlids. Haplochromine cichlids of one of the two lineages that seeded the Lake Victoria radiation recently arrived in Lake Chala, a lake perfectly suited for within-lake cichlid speciation. Here, we infer the colonization and demographic history, quantify phenotypic, ecological and genomic diversity and diversification, and investigate the selection regime to ask if the population shows signs of diversification resembling the onset of adaptive radiation. We find that since their arrival in the lake, haplochromines have colonized a wide range of depth habitats associated with ecological and morphological expansion and the beginning of phenotypic differentiation and potentially nascent speciation, consistent with the very early onset of an adaptive radiation process. Moreover, we demonstrate evidence of rugged phenotypic fitness surfaces, indicating that current ecological selection may contribute to the phenotypic diversification.
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- 2018
44. Evolutionary divergence in life history traits among populations of the Lake Malawi cichlid fish Astatotilapia calliptera
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Lukas Rüber, Paul J. Parsons, Martin J. Genner, and Jon R. Bridle
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0106 biological sciences ,0301 basic medicine ,Avian clutch size ,Population ,Biology ,Mouthbrooder ,010603 evolutionary biology ,01 natural sciences ,phenotypic plasticity ,Life history theory ,03 medical and health sciences ,Cichlid ,Adaptive radiation ,14. Life underwater ,education ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,egg size ,education.field_of_study ,Ecology ,biology.organism_classification ,Genetic divergence ,Haplochromine ,030104 developmental biology ,570 Life sciences ,biology ,growth rate ,adaptive radiation ,FST-QST - Abstract
During the early stages of adaptive radiation, populations diverge in life history traits such as egg size and growth rates, in addition to eco-morphological and behavioural characteristics. However, there are few studies of life history divergence within ongoing adaptive radiations. Here we studied Astatotilapia calliptera, a maternal mouthbrooding cichlid fish within the Lake Malawi haplochromine radiation. This species occupies a rich diversity of habitats, including the main body of Lake Malawi, as well as peripheral rivers and shallow lakes. We used common garden experiments to test for life-history divergence among populations, focussing on clutch size, duration of incubation, egg mass, offspring size and growth rates. In a first experiment we found significant differences among populations in average clutch size and egg mass, and larger clutches were associated with smaller eggs. In a second experiment, we found significant differences among populations in brood size, duration of incubation, juvenile length when released, and growth rates. Larger broods were associated with smaller juveniles when released and shorter incubation times. Although juvenile growth rates differed between populations, these were not strongly related to initial size on release. Overall, differences in life history characters among populations were not predicted by major habitat classifications (Lake Malawi or peripheral habitats) or population genetic divergence (microsatellite-based FST). We suggest that the observed patterns are consistent with local selective forces driving the observed patterns of trait divergence. The results provide strong evidence of evolutionary divergence and covariance of life history traits among populations within a radiating cichlid species, highlighting opportunities for further work to identify the processes driving the observed divergence.
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- 2017
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45. Fast adaptive responses in the oral jaw of Lake Victoria cichlids
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Ellen S. Hoogwater, Jan H. Wanink, Jacobus Cornelis van Rijssel, Frans Witte, Ronald C. van der Stelt, Kevin V. Spits, Elize van Reenen, and Mary A. Kishe-Machumu
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Phenotypic plasticity ,Premaxilla ,biology ,Ecology ,media_common.quotation_subject ,Microevolution ,Zoology ,biology.organism_classification ,Competition (biology) ,Predation ,Haplochromine ,medicine.anatomical_structure ,Cichlid ,Adaptive radiation ,Genetics ,medicine ,sense organs ,skin and connective tissue diseases ,General Agricultural and Biological Sciences ,Ecology, Evolution, Behavior and Systematics ,media_common - Abstract
Rapid morphological changes in response to fluctuating natural environments are a common phenomenon in species that undergo adaptive radiation. The dramatic ecological changes in Lake Victoria provide a unique opportunity to study environmental effects on cichlid morphology. This study shows how four haplochromine cichlids adapted their premaxilla to a changed diet over the past 30 years. Directly after the diet change toward larger and faster prey in the late 1980s, the premaxilla (upper jaw) changed in a way that is in agreement with a more food manipulating feeding style. During the 2000s, two zooplanktivorous species showed a reversal of morphological changes after returning to their original diet, whereas two other species showed no reversal of diet and morphology. These rapid changes indicate a potential for extremely fast adaptive responses to environmental fluctuations, which are likely inflicted by competition release and increase, and might have a bearing on the ability of haplochromines to cope with environmental changes. These responses could be due to rapid genetic change or phenotypic plasticity, for which there is ample evidence in cichlid fish structures associated with food capture and processing. These versatile adaptive responses are likely to have contributed to the fast adaptive radiation of haplochromines.
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- 2014
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46. Timing of population expansions within the Lake Malawi haplochromine cichlid fish radiation
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George F. Turner and Martin J. Genner
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education.field_of_study ,biology ,Ecology ,Population ,Diplotaxodon ,Aquatic Science ,biology.organism_classification ,Rhamphochromis ,Haplochromine ,Cichlid ,Adaptive radiation ,Species richness ,education ,Endemism - Abstract
Major environmental changes can trigger dramatic evolutionary change. Lake Malawi contains an adaptive radiation of more than 800 haplochromine species that have evolved within the last 2–4 million years. Using mitochondrial DNA sequences, we reconstructed temporal changes in effective size of 46 populations from 28 species within the flock. All populations showed expansions within the last million years, but timescales differed substantially. Offshore pelagic species of the genera Diplotaxodon and Rhamphochromis underwent rapid population expansions on average 175,000 and 290,000 years ago, respectively. By contrast, shallow-water benthic-living species underwent rapid population expansions within the last 50,000 years. These results suggest that populations of pelagic taxa persisted through major Pleistocene megadroughts between 160,000 and 90,000 years ago when the lake was smaller, shallower, more saline and turbid. They also suggest that populations of inshore demersal taxa were smaller or absent during these low stands, only expanding when the lake rose towards present levels. Given many shallow-water and benthic-living haplochromine species in Lake Malawi exhibit extreme local endemism, we suggest that many have originated since the last major lake rise. Such new ecological opportunity may have been critical for the evolution of high cichlid species richness that now characterises littoral habitats.
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- 2014
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47. Signal and preference divergence among populations of the non-endemic basal Lake Malawi cichlid fishAstatotilapia calliptera(Perciformes: Cichlidae)
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George F. Turner and Alexandra M. Tyers
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education.field_of_study ,biology ,Ecology ,Population ,Allopatric speciation ,Zoology ,Reproductive isolation ,biology.organism_classification ,Perciformes ,Haplochromine ,Mate choice ,Cichlid ,Adaptive radiation ,parasitic diseases ,education ,Ecology, Evolution, Behavior and Systematics - Abstract
In Lake Malawi and Lake Victoria, cichlid fishes have diversified into hundreds of species, many reproductively isolated by mate choice. Territorial males tend to be more aggressive to similar-coloured males, facilitating coexistence of divergent colour morphs or species. Behavioural mate choice and aggression biases of species and allopatric populations of specialized rocky shore cichlids are influenced by divergent signals such as male colour. Believed to be basal to the Lake Malawi haplochromine radiation, and inhabiting shallow weedy areas of the lake and neighbouring water bodies, Astatotilapia calliptera also shows allopatric variation in colour. Here, it is demonstrated that such signal divergence is associated with tendencies of females to mate with males of their own population and also for males to preferentially attack males of their own population, indicating that preference divergence related to signal divergence in allopatry may have operated throughout the adaptive radiation of the Malawian cichlids. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 180–188.
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- 2013
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48. Comparative transcriptomics of anal fin pigmentation patterns in cichlid fishes
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Langyu Gu, Nicolas Boileau, Zuzana Musilová, M. Emília Santos, Walter Salzburger, Laura Baldo, and Universitat de Barcelona
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Fish Proteins ,0301 basic medicine ,Candidate gene ,East African cichlids ,Astatotilapia burtoni ,Egg-spot ,Anal Canal ,Zoology ,Skin Pigmentation ,Evolution, Molecular ,03 medical and health sciences ,Species Specificity ,Color of animals ,Phylogenetics ,Cichlid ,Genetics ,Animals ,14. Life underwater ,Phylogeny ,Diversity ,biology ,Pigmentation ,Sequence Analysis, RNA ,Gene Expression Profiling ,Fishes ,Fish fin ,Color dels animals ,Cichlids ,Peixos ,biology.organism_classification ,Expressió gènica ,Phenotype ,Gene expression profiling ,Haplochromine ,Blotches ,030104 developmental biology ,Gene Expression Regulation ,Animal Fins ,Gene expression ,Research Article ,Biotechnology - Abstract
Background: Understanding the genetic basis of novel traits is a central topic in evolutionary biology. Two novel pigmentation phenotypes, egg-spots and blotches, emerged during the rapid diversification of East African cichlid fishes. Egg-spots are circular pigmentation markings on the anal fins of hundreds of derived haplochromine cichlids species, whereas blotches are patches of conspicuous anal fin pigmentation with ill-defined boundaries that occur in few species that belong to basal cichlid lineages. Both traits play an important role in the breeding behavior of this group of fishes. Knowledge about the origin, homology and underlying genetics of these pigmentation traits is sparse. Results: Here, we present a comparative transcriptomic and differential gene expression analysis of egg-spots and blotches. We first conducted an RNA sequencing experiment where we compared egg-spot tissue with the remaining portion of egg-spot-free fin tissue using six individuals of Astatotilapia burtoni. We identified 1229 differentially expressed genes between the two tissue types. We then showed that rates of evolution of these genes are higher than average estimated on whole transcriptome data. Using quantitative real-time PCR, we found that 29 out of a subset of 46 differentially expressed genes showed an analogous expression pattern in another haplochromine species' egg-spots, Cynotilapia pulpican, strongly suggesting that these genes are involved in the egg-spot phenotype. Among these are the previously identified egg-spot gene fhl2a, two known patterning genes (hoxC12a and bmp3) as well as other pigmentation related genes such as asip. Finally, we analyzed the expression patterns of the same gene subset in two species that feature blotches instead of egg-spots, one haplochromine species (Pseudocrenilabrus philander) and one ectodine species (Callochromis macrops), revealing that the expression patterns in blotches and egg-spots are rather distinct. Conclusions: We identified several candidate genes that will serve as an important and useful resource for future research on the emergence and diversification of cichlid fishes' egg-spots. Only a limited degree of conservation of gene expression patterns was detected between the egg-spots of the derived haplochromines and blotches from ancestral haplochromines, as well as between the two types of blotches, suggesting an independent origin of these traits. Keywords: Pigmentation, Diversity, Egg-spot, Blotches, East African cichlids, Gene expression Abbreviations: Bp, Base pairs; CDS, Coding sequences; CT, Threshold cycle; DE, Differentially expressed; dN/dS, Ratio of non-synonymous substitutions over synonymous substitutions; FDR, False discovery rate; GLM, Generalized linear model; GO, Gene ontology; qPCR, Quantitative real-time polymerase chain reaction; RNAseq, RNA sequencing; RSEM, RNA-Seq by Expectation-Maximization; UTR, Untranslated region
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- 2016
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49. Correlated evolution of short wavelength sensitive photoreceptor sensitivity and color pattern in Lake Malawi cichlids
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Suzanne Joneson, Jay Neitz, Michael J. Pauers, and James A. Kuchenbecker
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phylogenetic independent contrasts ,0106 biological sciences ,0301 basic medicine ,Visual perception ,genetic structures ,Ecology and Evolution ,lcsh:Evolution ,Correlated evolution ,Biology ,010603 evolutionary biology ,01 natural sciences ,Predation ,03 medical and health sciences ,Cichlid ,lcsh:QH540-549.5 ,Ultraviolet light ,lcsh:QH359-425 ,14. Life underwater ,Ecology, Evolution, Behavior and Systematics ,Visual ecology ,ultraviolet photoreception ,Ecology ,Phylogenetic tree ,Cichlids ,biology.organism_classification ,Haplochromine ,030104 developmental biology ,Spectral sensitivity ,Mate choice ,Evolutionary biology ,Lake Malawi ,lcsh:Ecology - Abstract
For evolutionary ecologists, the holy grail of visual ecology is to establish an unambiguous link between photoreceptor sensitivity, the spectral environment, and the perception of specific visual stimuli (e.g., mates, food, predators, etc.). Due to the bright nuptial colors of the males, and the role female mate choice plays in their evolution, the haplochromine cichlid fishes of the African great lakes are favorite research subjects for such investigations. Despite this attention, current evidence is equivocal; while distinct correlations among photoreceptor sensitivity, photic environment, and male coloration exist in Lake Victorian haplochromines, attempts to find such correlations in Lake Malawian cichlids have failed. Lake Malawi haplochromines have a wide variability in their short-wavelength-sensitive photoreceptors, especially compared to their mid- and long-wavelength-sensitive photoreceptors; these cichlids also vary in the degree to which they express one of three basic color patterns (vertical bars, horizontal stripes, and solid patches of colors), each of which is likely used in a different form of communication. Thus, we hypothesize that, in these fishes, spectral sensitivity and color pattern have evolved in a correlated fashion to maximize visual communication; specifically, ultraviolet sensitivity should be found in vertically-barred species to promote ‘private’ communication, while striped species should be less likely to have ultraviolet sensitivity, since their color pattern carries ‘public’ information. Using phylogenetic independent contrasts, we found that barred species had strong sensitivity to ultraviolet wavelengths, but that striped species typically lacked sensitivity to ultraviolet light. Further, the only variable, even when environmental variables were simultaneously considered, that could predict ultraviolet sensitivity was color pattern. We also found that, using models of correlated evolution, color pattern and ultraviolet sensitivity are correlated in Lake Malawi cichlid evolution, with the likely ancestor being a vertically-barred, ultraviolet-sensitive species, the descendants of which lost both ultraviolet sensitivity and a barred color pattern. These results, indicating that communication of ‘public’ and ‘private’ signals is mediated via differing perceptions of color patterns, suggest a functional connection between visual sensitivity and colour pattern, a novel finding in Lake Malawi cichlids.
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- 2016
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50. Digest: For ecologically similar Andean birds, gene flow and plumage uniformity go hand in hand*
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Sheela P. Turbek
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0301 basic medicine ,education.field_of_study ,biology ,Population ,biology.organism_classification ,Gene flow ,Haplochromine ,03 medical and health sciences ,030104 developmental biology ,Taxon ,Plumage ,Evolutionary biology ,Sexual selection ,Genetic variation ,Genetics ,Heliconius ,General Agricultural and Biological Sciences ,education ,Ecology, Evolution, Behavior and Systematics - Abstract
The idea that genetic differentiation can proceed despite genetic exchange between divergent lineages is gaining support in evolutionary biology (Nosil 2008). Though theoretically difficult to achieve because interbreeding counteracts population differentiation, divergence with gene flow has shaped the evolutionary histories of diverse organisms including Heliconius butterflies (Martin et al. 2013) and Galapagos finches (de Leon et al. 2010). In some taxa, such as the haplochromine cichlids, hybridization may even have played a creative role, providing the genetic variation necessary to fuel adaptive radiations (Meier et al. 2017). This article is protected by copyright. All rights reserved
- Published
- 2017
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