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Genetic diversity is a fundamental component of biodiversity. Examination of global patterns of genetic diversity can help highlight mechanisms underlying species diversity, though a recurring challenge has been that patterns may vary by molecular marker. Here, we compiled 6862 observations of genetic diversity from 492 species of marine fish and tested among hypotheses for diversity gradients: the founder effect hypothesis, the kinetic energy hypothesis, and the productivity-diversity hypothesis. We fit generalized linear mixed effect models (GLMMs) and explored the extent to which various macroecological drivers (latitude, longitude, temperature (SST), and chlorophyll-a concentration) explained variation in genetic diversity. We found that mitochondrial genetic diversity followed geographic gradients similar to those of species diversity, being highest near the Equator, particularly in the Coral Triangle, while nuclear genetic diversity did not follow clear geographic patterns. Despite these differences, all genetic diversity metrics were correlated with chlorophyll-a concentration, while mitochondrial diversity was also positively associated with SST. Our results provide support for the kinetic energy hypothesis, which predicts that elevated mutation rates at higher temperatures increase mitochondrial but not necessarily nuclear diversity, and the productivity-diversity hypothesis, which posits that resource-rich regions support larger populations with greater genetic diversity. Overall, these findings reveal how environmental variables can influence mutation rates and genetic drift in the ocean, caution against using mitochondrial macrogenetic patterns as proxies for whole-genome diversity, and aid in defining global gradients of genetic diversity.

Fungi use the accessory gene content of their pangenomes to adapt to their environments. While gene presence-absence variation contributes to shaping accessory gene reservoirs, the genomic contexts that shape these events remain unclear. Since pangenome studies are typically species-wide and do not analyze different populations separately, it is yet to be uncovered whether presence-absence variation patterns and mechanisms are consistent across populations. Fungal plant pathogens are useful models for studying presence-absence variation because they rely on it to adapt to their hosts, and members of a species often infect distinct hosts. We analyzed gene presence-absence variation in the blast fungus, Magnaporthe oryzae (syn. Pyricularia oryzae), and found that presence-absence variation genes involved in host-pathogen and microbe-microbe interactions may drive the adaptation of the fungus to its environment. We then analyzed genomic and epigenomic features of presence-absence variation and observed that proximity to transposable elements, gene GC content, gene length, expression level in the host, and histone H3K27me3 marks were different between presence-absence variation genes and conserved genes. We used these features to construct a model that was able to predict whether a gene is likely to experience presence-absence variation with high precision (86.06%) and recall (92.88%) in M. oryzae. Finally, we found that presence-absence variation genes in the rice and wheat pathotypes of M. oryzae differed in their number and their genomic context. Our results suggest that genomic and epigenomic features of gene presence-absence variation can be used to better understand and predict fungal pangenome evolution. We also show that substantial intra-species variation can exist in these features.

Invasive commensal rodents are the source of significant harms across diverse ecosystems globally, including biodi­versity loss on islands, economic damage in agricultural settings, and disease spread in urban areas. Genetic tools can provide unique insights and solutions for rodent management or eradication, adding to the toolbox of integrated pest management opera­tions. In real world conditions, the utility of genetic tools for rodent management is constrained by ecological factors such as mating and dispersal behavior, landscape variation, and ongoing management strategies. Here we describe two distinct uses of genetic tools for rodent management and their ecological considerations. First, we describe how patterns of genetic connectivity can inform the establishment of functional management units, discern among scenarios leading to island eradication failure, and provide insights into rodent management outcomes. Second, we discuss the utility and risks of using gene drive systems to eradicate invasive house mice from island environments. We describe aspects of risk assessment and mitigation as well as the utility of computational models for improving gene drive preparedness. Together, we outline the importance of ecologically-informed implementation strategies when using genetic tools, both currently available and in development, for the management of commensal rodents.

Advancements in genome assembly and sequencing technology have made whole genome sequence (WGS) data and reference genomes accessible to study polyploid species. Compared to popular reduced-representation sequencing approaches, the genome-wide coverage and greater marker density provided by WGS data can greatly improve our understanding of polyploid species and polyploid biology. However, biological features that make polyploid species interesting also pose challenges in read mapping, variant identification, and genotype estimation. Accounting for characteristics in variant calling like allelic dosage uncertainty, homology between subgenomes, and variance in chromosome inheritance mode can reduce errors. Here, I discuss the challenges of variant calling in polyploid WGS data and discuss where potential solutions can be integrated into a standard variant calling pipeline.

Life cycles with a prolonged haploid phase are thought to be correlated with greater rates of selfing and asexual reproduction. In red algae, recent population genetic studies have aimed to test this prediction but have mostly focused on marine species with separate sexes. We characterized the reproductive system of the obligately monoicous (i.e., hermaphroditic) freshwater red alga Batrachospermum gelatinosum and predicted that we would find genetic signatures of uniparental reproduction because of its haploid‐diploid life cycle. We sampled 18 sites and genotyped 311 gametophytes with 10 polymorphic microsatellite loci to describe the reproductive system. Genotypic richness was low (<0.5) and pareto β values (describing clonal membership) were <0.7 for most sites. In taxa with separate sexes, these patterns are typically indicative of asexual reproduction. However, the genetic consequences of selfing in monoicous gametophytes are indistinguishable from those caused by asexual processes. Since we sampled gametophytes and have not yet genotyped the chantransia (i.e., the diploid phase), we interpreted low diversity as a signature of intragametophytic selfing. Additionally, to understand the factors that drive selfing, we tested latitude and several other environmental variables, but none was significantly correlated with the genetic variation we observed. Nevertheless, future studies should genotype the chantransia to measure observed heterozygosity among other summary statistics to disentangle the effects of selfing versus asexual reproduction. Together, these data, coupled with further characterization of abiotic factors that influence population genetic patterns, will allow us to test potential drivers of reproductive system evolution. [ABSTRACT FROM AUTHOR]

ABSTRACT Describing naturally occurring genetic variation is a fundamental goal of molecular phylogeography and population genetics. Popular methods for this task include STRUCTURE, a model‐based algorithm that assigns individuals to genetic clusters, and principal component analysis (PCA), a parameter‐free method. The ability of STRUCTURE to infer mixed ancestry makes it popular for documenting natural hybridisation, which is of considerable interest to evolutionary biologists, given that such systems provide a window into the speciation process. Yet, STRUCTURE can produce misleading results when its underlying assumptions are violated, like when genetic variation is distributed continuously across geographic space. To test the ability of STRUCTURE and PCA to accurately distinguish admixture from continuous variation, we use forward‐time simulations to generate population genetic data under three demographic scenarios: two involving admixture and one with isolation by distance (IBD). STRUCTURE and PCA alone cannot distinguish admixture from IBD, but complementing these analyses with triangle plots, which visualise hybrid index against interclass heterozygosity, provides more accurate inference of demographic history, especially in cases of recent admixture. We demonstrate that triangle plots are robust to missing data, while STRUCTURE and PCA are not, and show that setting a low allele frequency difference threshold for ancestry‐informative marker (AIM) identification can accurately characterise the relationship between hybrid index and interclass heterozygosity across demographic histories of admixture and range expansion. While STRUCTURE and PCA provide useful summaries of genetic variation, results should be paired with triangle plots before admixture is inferred. [ABSTRACT FROM AUTHOR]

Ferula huber‐morathii is an endemic and medicinally important plant. This species is distributed in eight Turkish localities, including three newly identified ones. Its extent of occurrence and area of occupancy is determined to be 3963 km2 and 32 km2 respectively. All localities are characterized by East Mediterranean and sub‐Mediterranean precipitation regimes; however, temperatures increase excessively and precipitation decreases during the flowering period of the species. The population sizes are quite small, and the number of reproducing individuals in some populations is below ten. Analyses of ISSR markers showed the percentage of polymorphic loci to be 94% at the species level and 56% at the population level. The level of genetic differentiation (measured by GST) was 0.37 and the estimated level of gene flow among populations (NM) was 0.84. The percentage of variance occurring within and among populations, determined by AMOVA, was 75% and 25%, respectively. STRUCTURE analysis revealed two genetic clusters of individuals with a geographic structure, similar to that found in UPGMA and an ordination analysis. Some populations turned out to have both low numbers of individuals and low genetic diversity. Since many of the populations are subject to anthropogenic disturbance, the species should remain in the EN category. At the same time, it is suggested that a new in‐situ conservation area should be created around nearby dams, situated in the same climate area as the currently known populations. [ABSTRACT FROM AUTHOR]

Practical approaches have become a standard in many scientific disciplines, including population genetics. By analysing properly selected datasets, students can calculate parameters and draw conclusions about genetic diversity, differentiation and evolution of populations with higher efficiency than if based exclusively on theoretical lessons. However, preparing the appropriate datasets is a hard task and a wrong selection can spoil a well-intended activity. Here we present SimHyb 2, a software tool specifically intended to support a full understanding of evolutionary forces by students and to help the teacher to prepare adequate datasets and examples for practice. It simulates the course of a mixed population under user-defined reproductive and evolutionary conditions, providing fully traceable pedigrees of individuals. SimHyb2 is specifically intended for the analysis of long-term hybridisation and introgression, covering a gap in the software available to date. Outputs can be easily adapted for downstream analysis with other popular tools as GenAlEx or Structure. Thus, SimHyb 2 is very suitable for project-based-learning approaches: students can produce their own datasets in different scenarios of genetic drift, migration, selective advantage, and reproductive success. Satisfactory results from its ongoing utilisation in higher education and research are reported. [ABSTRACT FROM AUTHOR]

The freshwater red alga Batrachospermum gelatinosum has a well‐documented distribution spanning historically glaciated and unglaciated eastern North America. This alga has no known desiccation‐resistant propagule; thus, long‐distance dispersal events are likely rare. We predicted strong genetic structure among drainage basins and admixture among sites within basins. We predicted greater genetic diversity at lower latitude sites because they likely serve as refugia and the origin of northward, post‐Pleistocene range expansion. We used 10 microsatellite loci to investigate genetic diversity from 311 gametophytes from 18 sites in five major drainage basins: South Atlantic Gulf, Mid‐Atlantic, Ohio River, Great Lakes, and Northeast. Our data showed strong genetic partitioning among drainage basins and among sites within basins, yet no isolation by distance was detected. Genetic diversity varied widely among sites and was not strictly related to latitude as predicted. The results from B. gelatinosum provide strong support that each stream site contributes to the unique genetic variation within the species, potentially due to limited dispersal and the prevailing reproductive mode of intragametophytic selfing. Simulations of migration suggested post‐Pleistocene dispersal from the Mid‐Atlantic. Batrachospermum gelatinosum potentially persisted in refugia that were just south of the ice margins rather than in the southernmost part of its range. Research of other taxa with similar ranges could determine whether these results are generally applicable for freshwater red algae. Nevertheless, these results from B. gelatinosum add to the growing literature focused on the patterns and genetic consequences of post‐Pleistocene range expansion by eastern North American biota. [ABSTRACT FROM AUTHOR]

ABSTRACT Montane landscapes present an array of abiotic challenges that drive adaptive evolution amongst organisms. These adaptations can promote habitat specialisation, which may heighten the risk of extirpation from environmental change. For example, higher metabolic rates in an endothermic species may contribute to heightened cold tolerance, whilst simultaneously limiting heat tolerance. Here, using the climate‐sensitive American pika (Ochotona princeps), we test for evidence of intraspecific adaptive variation amongst environmental gradients across the Intermountain West of North America. We leveraged results from previous studies on pika adaptation to generate a custom nuclear target enrichment design to sequence several hundred candidate genes related to cold, hypoxia and dietary detoxification. We also applied a ‘genome skimming’ approach to sequence mitochondrial DNA. Using genotype–environment association tests, we identified rare genomic variants associated with elevation and temperature variation amongst populations. Amongst mitochondrial genes, we identified intraspecific variation in selective signals and significant changes to the amino acid property equilibrium constant, which may relate to electron transport chain efficiency. These results illustrate a complex dynamic of adaptive variation amongst O. princeps where lineages and populations have adapted to unique regional conditions. Some of the clearest signals of selection were in a genetic lineage that includes pikas of the Great Basin region, which is also where recent localised extirpations have taken place and highlights the risk of losing adaptive alleles during environmental change. [ABSTRACT FROM AUTHOR]

Gene drives have great potential for suppression of pest populations and removal of exotic invasive species. CRISPR homing suppression drive is a powerful but unconfined drive, posing risks of uncontrolled spread. Thus, developing methods for confining a gene drive is of great significance. Tethered drive combines a confined system such as Toxin‐Antidote Recessive Embryo drive with a strong drive such as a homing suppression drive. It can prevent the homing drive from spreading beyond the confined drive and can be constructed readily, giving it good prospects for future development. However, we have found that care must be taken when deploying tethered drive systems in some scenarios. Simulations of tethered drive in a panmictic population model reveal that successful deployment requires a proper release ratio between the two components, tailored to prevent the suppression drive from eliminating the confined system before it has the chance to spread. Spatial models where the population moves over a one‐dimensional landscape display a more serious phenomenon of drive wave interference between the two tethered drive components. If the faster suppression drive wave catches up to the confined drive wave, success is still possible, but it is dependent on drive performance and ecological parameters. Two‐dimensional simulations further restrict the parameter range for drive success. Thus, careful consideration must be given to drive performance and ecological conditions, as well as specific release proposals for potential application of tethered drive systems. [ABSTRACT FROM AUTHOR]

Many human pathogens, including malaria, dengue, influenza, Streptococcus pneumoniae, and cytomegalovirus, coexist as multiple genetically distinct strains. Understanding how these multistrain pathogens evolve is of critical importance for forecasting epidemics and predicting the consequences of vaccination. One factor believed to play an important role is naturally acquired immunity. Consequently, a large body of research has sought to predict how acquired immunity molds the genomics of pathogen populations (i.e., what shapes pathogen strain structure). The diversity of existing models has resulted in conflicting evolutionary predictions and has sparked an ongoing debate about which predictions are most broadly applicable. Here, we adopt a multilocus population genetics perspective that unifies the predictions of existing models. We identify three key factors that determine the role of naturally acquired immunity in the evolution of pathogen strain structure: i) the strength and specificity of immune protections, ii) the dynamic immunological landscape, and iii) the number of loci coding for the antigens of the pathogen. Isolating and discussing these three factors clarifies the relationship among previous models of multistrain dynamics, and establishes a solid theoretical foundation for the study of the evolutionary epidemiology of multistrain pathogens. [ABSTRACT FROM AUTHOR]

Background: The sect. Chrysantha Chang of plants with yellow flowers of Camellia species as the "Queen of the Tea Family", most of these species are narrowly distributed endemics of China and are currently listed Grde-II in National Key Protected Wild Plant of China. They are commercially important plants with horticultural medicinal and scientific research value. However, the study of the sect. Chrysantha species genetics are still in its infancy, to date, the mitochondrial genome in sect. Chrysantha has been still unexplored. Results: In this study, we provide a comprehensive assembly and annotation of the mitochondrial genomes for four species within the sect. Chrysantha. The results showed that the mitochondrial genomes were composed of closed-loop DNA molecules with sizes ranging from 850,836 bp (C. nitidissima) to 1,098,121 bp (C. tianeensis) with GC content of 45.71–45.78% and contained 48–58 genes, including 28–37 protein-coding genes, 17–20 tRNA genes and 2 rRNA genes. We also examined codon usage, sequence repeats, RNA editing and selective pressure in the four species. Then, we performed a comprehensive comparison of their basic structures, GC contents, codon preferences, repetitive sequences, RNA editing sites, Ka/Ks ratios, haplotypes, and RNA editing sites. The results showed that these plants differ little in gene type and number. C. nitidissima has the greatest variety of genes, while C. tianeensis has the greatest loss of genes. The Ka/Ks values of the atp6 gene in all four plants were greater than 1, indicating positive selection. And the codons ending in A and T were highly used. In addition, the RNA editing sites differed greatly in number, type, location, and efficiency. Twelve, six, five, and twelve horizontal gene transfer (HGT) fragments were found in C. tianeensis, Camellia huana, Camellia liberofilamenta, and C. nitidissima, respectively. The phylogenetic tree clusters the four species of sect. Chrysantha plants into one group, and C. huana and C. liberofilamenta have closer affinities. Conclusions: In this study, the mitochondrial genomes of four sect. Chrysantha plants were assembled and annotated, and these results contribute to the development of new genetic markers, DNA barcode databases, genetic improvement and breeding, and provide important references for scientific research, population genetics, and kinship identification of sect. Chrysantha plants. [ABSTRACT FROM AUTHOR]

Grasping the genetic structure of marine fish populations is vital for comprehending species connectivity patterns and determining the appropriate spatiotemporal scales for conservation management strategies. Here, we analyzed the population genetics of the Orangefin Ponyfish (Photopectoralis bindus Valenciennes, 1835) by examining a portion of the gene coding for the mitochondrial cytochrome c oxidase subunit I. The aim was to evaluate the haplotype pattern, genetic structure, demographic history, as well as the influence of ecological connectivity through the Qiongzhou Strait on the distribution patterns of this species in the northern South China Sea and the Beibu Gulf. In total, 257 specimens yielded only 13 haplotypes, with the predominant haplotype present at all sampling locations. The analysis revealed a "star-like" haplotype pattern, indicating low levels of both haplotype and nucleotide diversity. Additionally, a small but significant genetic structure was observed between the coastal regions flanking the Leizhou Peninsula. These patterns in the haplotype network and genetic structure may be significantly influenced by contemporary currents, particularly through the connectivity of the Qiongzhou Strait. Tajima's D and Fu's Fs demonstrated pronouncedly negative values, along with a unimodal mismatch distribution, suggested a recent demographic expansion of Photopectoralis bindus during the late Pleistocene, likely influenced by fluctuations in sea levels. [ABSTRACT FROM AUTHOR]

Genetic variation among populations is reflected in biogeographic patterns for many species, but general rules of spatial genetic variation have not been established. In this paper, we establish a theoretical framework based on projecting environmental Grinellian niches back through time to relate the present geographic distribution of population genetic structure to a given species' historical evolutionary context. Thanks to advances in next‐generation sequencing technologies, as well as more accurate climate models and the amassing of information stored in biological collections, it is possible to implement this theoretical framework directly. We develop a case study of the tassel‐eared squirrel Sciurus aberti to jointly analyze spatial, environmental, and genetic data to predict the historical endemic area of this species. Our results reveal that in cases of genetic isolation by geographic distance, the prevalence of environmental suitability over time corresponds to the genetic fixation index (Fst) of populations with respect to a source population. Populations closer to the historical endemic area show higher genetic diversity and a lower Fst value. This empirical example relates back to the theoretical framework, allowing two further advances: 1) a layer of biogeographic explanation for the results obtained from population genomic methods; and 2) predictive maps of this genetic structure to support biodiversity conservation efforts. Overall, this work advances a perspective that integrates population genetics with historical patterns of species distribution. The limitations posed in the theoretical framework should be considered before implementing the suitability prevalence area (SPA) in a general way over different taxa. Otherwise, the predictability of the genetic diversity of populations as a product of environmental stability over time may not be adequate. [ABSTRACT FROM AUTHOR]

ABSTRACT Impalas are unusual among bovids because they have remained morphologically similar over millions of years—a phenomenon referred to as evolutionary stasis. Here, we sequenced 119 whole genomes from the two extant subspecies of impala, the common (Aepyceros melampus melampus) and black‐faced (A. m. petersi) impala. We investigated the evolutionary forces working within the species to explore how they might be associated with its evolutionary stasis as a taxon. Despite being one of the most abundant bovid species, we found low genetic diversity overall, and a phylogeographic signal of spatial expansion from southern to eastern Africa. Contrary to expectations under a scenario of evolutionary stasis, we found pronounced genetic structure between and within the two subspecies with indications of ancient, but not recent, gene flow. Black‐faced impala and eastern African common impala populations had more runs of homozygosity than common impala in southern Africa, and, using a proxy for genetic load, we found that natural selection is working less efficiently in these populations compared to the southern African populations. Together with the fossil record, our results are consistent with a fixed‐optimum model of evolutionary stasis, in which impalas in the southern African core of the range are able to stay near their evolutionary fitness optimum as a generalist ecotone species, whereas eastern African impalas may struggle to do so due to the effects of genetic drift and reduced adaptation to the local habitat, leading to recurrent local extinction in eastern Africa and re‐colonisation from the South. [ABSTRACT FROM AUTHOR]

Introduction: Since its introduction about a decade ago, target enrichment sequencing of ultraconserved elements (UCEs) has proven to be an invaluable tool for studies across evolutionary scales, and thus employed from population genetics, to historical biogeography as well as deep-time phylogenetics. Here, we present the first probe set targeting UCEs in crustaceans, specifically designed for decapods and tested beyond decapods in other malacostracan lineages. Methods: Probes were designed using published genomes of nine decapod and one peracarid species, as well as raw Nanopore long reads of one additional brachyuran species. The final probe set consists of about 20,000 probes, targeting 1,384 unique UCE loci. We compiled a dataset across Malacostraca, as well as datasets of a deep-sea squat lobster genus, and an intertidal mangrove crab species, to test the probe set at different phylogenetic levels (i.e., class, order, genus, within species). Results: Final mean UCE recovery from fresh samples across Malacostraca was 568 loci, with up to 847 and 658 loci recovered from decapod and non-decapod species, respectively. Final mean recovery from fresh samples in the genus- and within species-level datasets was 849 and 787 loci, respectively. Up to several hundreds of UCEs were recovered from historicalmuseum specimens (10 to > 150 years old), that were included in all datasets. UCE-based phylogenies largely reflected the known relationships of the included taxa, and we were able to infer population differentiation based on >600 SNPs extracted from the species-level dataset. Discussion: Our results showcase the versatility of this UCE probe set, yielding informative data from phylogenetic as well as population-genetic datasets. They demonstrate once more that UCEs are a promising technique for leveraging museum specimens for genomic studies, and overall highlight the probe set's potential for crustacean evolutionary studies. [ABSTRACT FROM AUTHOR]

The study of the state of Baikal endemic sponge populations is of great interest because of the occurrence of mass mortalities and disease in recent decades. To identify possible signs of species vulnerability to extinction, it is crucial to develop appropriate genetic markers that help developing measures for conservation.In this paper, we describe the population genetic structure of the Baikal endemic sponge Lubomirskia baikalensis examined with the set of microsatellite markers we developed. We analysed 251 samples from eight locations that cover all three basins of Lake Baikal.A genetic subdivision into three clusters was revealed. Such a structure can be explained mainly by the low ability of larvae to disperse.Despite the presence of dead and diseased individuals in all studied locations, all populations were in Hardy–Weinberg equilibrium and no bottleneck effect was found at all.This is the first time that a genetic connectivity study has been performed for L. baikalensis, a species endemic of Lake Baikal.Reconstruction of the changes in the effective population size agrees with the results obtained during drill sample analysis and it demonstrates that the effective population size was 55.5 times lower about 24,000 years ago, which indicates that apparently there is no threat of extinction of the Baikal endemic sponges at present. [ABSTRACT FROM AUTHOR]

Two subspecies of the Yellow-throated Woodland Warbler Phylloscopus ruficapilla (family Phylloscopidae) have been recognised in South Africa based on the extent and intensity of yellow colouration. Our previous multi-locus population genetic survey across much of the Eastern Cape and southern KwaZulu-Natal provinces, conducted from 2017 to 2023, revealed a single homogenous regional population. That finding, derived from 93 individuals sampled from nine sites—six northeast of the Great Kei River (n = 72) and three to the southwest (n = 21)—did not support a subspecies boundary near the Great Kei River. Here, using 188 publicly archived photographic records for this species in South Africa, we show that the phenotypes of both subspecies are present on either side of this divide. The observed genetic homogeneity and lack of clear phenotypic vicariance suggest that P. ruficapilla is more dispersive than currently appreciated, and that the plumage-based subspecies may not represent significant population-level differences. [ABSTRACT FROM AUTHOR]

Characterizing the genetic diversity of a species is crucial for understanding the factors that influence its local dispersion and population dynamics. Additionally, it provides insights into local processes that may affect the distribution of other species. Lineus sanguineus (Rathke, 1799) is a widely distributed species commonly found on fouling fauna along rocky shores. This species can reproduce asexually by fissiparity, and its pilidium larva facilitates dispersal, similar to other heteronemerteans. The present study utilized a population genetics approach combined with Ecological Niche Modeling analysis to evaluate L. sanguineus populations along the Brazilian coast. We used sequences from two mtDNA regions, 16S ribosomal RNA (16SrRNA) and cytochrome c oxidase subunit 1 (COI), and one nuclear region, Internal Transcribed Spacer 1 (ITS-1), from 85 specimens sampled in nine locations. Genetic diversity analysis revealed greater genetic variation for the ITS-1 marker compared to mtDNA, as evidenced by higher intrapopulation diversity values. There was no clear geographic pattern, and the AMOVA analysis revealed low to moderate genetic structuring and high connectivity among sampled localities, with most of the genetic variation contained within populations. The pairwise FST results indicate high genetic structuring between the Northeast and localities along the South and Southeast of Atlantic coastlines. This pattern suggests that Brazilian oceanic currents play an important role in species connectivity. The paleodistribution pattern demonstrated that the colonization could have occured from the South to the Northeast of the continent. These results reinforce that sexual reproduction and larval dispersion play a vital role in the connectivity of these Southwest Atlantic populations and that oceanographic currents, rafting and artificial transport facilitate these processes. [ABSTRACT FROM AUTHOR]

Brachidontes variabilis (Krauss, 1848) is a common small mussel widely distributed in the intertidal zone of southern China. Firstly, we characterized four complete mitochondrial genomes of B. variabilis from four populations (Wanning, Yangjiang, Zhangzhou, and Shanwei) in Chinese waters. This study was the first to sequence and discribe the mitochondrial genome of B. variabilis, which comprised of 2 ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs) and 12 protein-coding genes (PCGs, lacking atp8). And then three PCGs fragments, including cytochrome oxidase subunit I (cox1, 558 bp), NADH dehydrogenase subunit 5 (nad5, 754 bp), and NADH dehydrogenase subunit 4 (nad4, 879 bp), were utilized to investigate the population genetics and demography. The cox1, nad5 and nad4 fragments revealed 55, 81, and 103 haplotypes, respectively. Results indicated high genetic diversity within populations (Hd > 0.5, Pi > 0.005) and little genetic differentiation among populations (FST<0.05), suggesting frequent gene exchanges. Further, the neutrality test and Extended Bayesian skyline plots (EBSPs) suggested that the four populations underwent population expansion at 0.9–1.1 Ma during the Pleistocene. In summary, this study on the mitochondrial genomes and population genetics of B. variabilis provides insights into the evolutionary history and demographic dynamics of this species in southern China. [ABSTRACT FROM AUTHOR]

Reproductive interference is defined as an interspecific interaction that reduces fitness via mating processes. Although its ecological and evolutionary consequences have attracted much attention, how reproductive interference affects the population genetic structures of interacting species is still unclear. In flowering plants, recent studies found that self-pollination can mitigate the negative effects of reproductive interference. Selfing-biased seed production is expected to increase population-level inbreeding and the selfing rate, and limits gene flow via pollinator outcrossing among populations. We examined the population genetics of the mixed-mating annual herb Commelina communis f. ciliata, focusing on reproductive interference by the sympatric competing congener C. communis using microsatellite markers. First, we found that almost all C. c. f. ciliata populations had relatively high inbreeding coefficients. Then, comparing sympatric and allopatric populations, we found evidence that reproductive interference from a competing congener increased the inbreeding coefficient and selfing rate. Allopatric populations exhibit varied selfing rates while almost all sympatric populations exhibit extremely high selfing rates, suggesting that population selfing rates were also influenced by unexamined factors, such as pollinator limitation. Besides, our findings revealed that reproductive interference from a competing congener did not limit gene flow among populations. We present the first report on how reproductive interference affects the genetic aspects of populations. Our results suggested that the high selfing rate of C. c. f. ciliata promotes its sympatric distribution with C. communis, even in the presence of reproductive interference, although it is not clear whether reproductive interference directly causes the high selfing rate. [ABSTRACT FROM AUTHOR]

Identifying and analysing isolated populations is critical for conservation. Isolation can make populations vulnerable to local extinction due to increased genetic drift and inbreeding, both of which should leave imprints of decreased genome‐wide heterozygosity. While decreases in heterozygosity among populations are frequently investigated, fewer studies have analysed how heterozygosity varies among individuals, including whether heterozygosity varies geographically along lines of discrete population structure or with continuous patterns analogous to isolation by distance. Here we explore geographical patterns of differentiation and individual heterozygosity in the threatened eastern barred bandicoot (Perameles gunnii) in Tasmania, Australia, using genomic data from 85 samples collected between 2008 and 2011. Our analyses identified two isolated demes undergoing significant genetic drift, and several areas of fine‐scale differentiation across Tasmania. We observed discrete genetic structures across geographical barriers and continuous patterns of isolation by distance, with little evidence of recent or historical migration. Using a recently developed analytical pipeline for estimating autosomal heterozygosity, we found individual heterozygosities varied within demes by up to a factor of two, and demes with low‐heterozygosity individuals also still contained those with high heterozygosity. Spatial interpolation of heterozygosity scores clarified these patterns and identified the isolated Tasman Peninsula as a location where low‐heterozygosity individuals were more common than elsewhere. Our results provide novel insights into the relationship between isolation‐driven genetic structure and local heterozygosity patterns. These may help improve translocation efforts, by identifying populations in need of assistance, and by providing an individualised metric for identifying source animals for translocation. [ABSTRACT FROM AUTHOR]

Right whales (genus Eubalaena) were among the first, and most extensively pursued, targets of commercial whaling. However, understanding the impacts of this persecution requires knowledge of the demographic histories of these species prior to exploitation. We used deep whole genome sequencing (~40×) of 12 North Atlantic (E. glacialis) and 10 Southwest Atlantic southern (E. australis) right whales to quantify contemporary levels of genetic diversity and infer their demographic histories over time. Using coalescent‐ and identity‐by‐descent–based modelling to estimate ancestral effective population sizes from genomic data, we demonstrate that North Atlantic right whales have lived with smaller effective population sizes (Ne) than southern right whales in the Southwest Atlantic since their divergence and describe the decline in both populations around the time of whaling. North Atlantic right whales exhibit reduced genetic diversity and longer runs of homozygosity leading to higher inbreeding coefficients compared to the sampled population of southern right whales. This study represents the first comprehensive assessment of genome‐wide diversity of right whales in the western Atlantic and underscores the benefits of high coverage, genome‐wide datasets to help resolve long‐standing questions about how historical changes in effective population size over different time scales shape contemporary diversity estimates. This knowledge is crucial to improve our understanding of the right whales' history and inform our approaches to address contemporary conservation issues. Understanding and quantifying the cumulative impact of long‐term small Ne, low levels of diversity and recent inbreeding on North Atlantic right whale recovery will be important next steps. [ABSTRACT FROM AUTHOR]

Reciprocal effects of adaptive radiations on the evolution of interspecific interactions, like parasitism, remain barely explored. We test whether the recent radiations of European whitefish (Coregonus spp.) across and within perialpine and subarctic lakes promote its parasite Proteocephalus fallax (Platyhelminthes: Cestoda) to undergo host repertoire expansion via opportunity and ecological fitting, or adaptive radiation by specialization. Using de novo genomic data, we examined P. fallax differentiation across lakes, within lakes across sympatric host species, and the contributions of host genetics versus host habitat use and trophic preferences. Whitefish intralake radiations prompted parasite host repertoire expansion in all lakes, whereas P. fallax differentiation remains incipient among sympatric fish hosts. Whitefish genetic differentiation per se did not explain the genetic differentiation among its parasite populations, ruling out codivergence with the host. Instead, incipient parasite differentiation was driven by whitefish phenotypic radiation in trophic preferences and habitat use in an arena of parasite opportunity and ecological fitting to utilize resources from emerging hosts. Whilst the whitefish radiation provides a substrate for the parasite to differentiate along the same water-depth ecological axis as Coregonus spp. the role of the intermediate hosts in parasite speciation may be overlooked. Parasite multiple-level ecological fitting to both fish and crustacean intermediate hosts resources may be responsible for parasite population substructure in Coregonus spp. We propose parasites' delayed arrival was key to the initial burst of postglacial intralake whitefish diversification, followed by opportunistic tapeworm host repertoire expansion and a delayed nonadaptive radiation cascade of incipient tapeworm differentiation. At the geographical scale, dispersal, founder events, and genetic drift following colonization of spatially heterogeneous landscapes drove strong parasite differentiation. We argue that these microevolutionary processes result in the mirroring of host–parasite phylogenies through phylogenetic tracking at macroevolutionary and geographical scales. [ABSTRACT FROM AUTHOR]

Summary: It is generally accepted that kelp populations have a metapopulation structure. Most zoospores settle near to their parent individual, and infrequent but long‐distance dispersal of zoospores contributes to gene flow between local populations. Population genetic analysis of single nucleotide polymorphism genotyping by MIG‐seq (i.e. multiplexed inter‐simple sequence repeats genotyping by sequencing) was performed on the dominant kelp, Eisenia bicyclis, in two areas: Kitsunezaki (a sheltered area) and Shimoda (an exposed site). Regional scale analysis of genetic structure was conducted at six sites in Kitsunezaki and three sites in Shimoda. When viewed on a regional scale based on the inbreeding coefficient within the local population, the inbreeding ratio was higher in Shimoda than in Kitsunezaki, probably as a result of the limited vertical zonal distribution in the exposed environment. Vertically wide distribution in the sheltered environment apparently enabled frequent crossing among individuals in Kitsunezaki. By contrast, when viewed on a local scale based on the pairwise kinship coefficient (FST) between populations, gene flow among local populations in Shimoda occurred over a wide area, but was limited in Kitsunezaki. In Shimoda, genetic exchange between local populations, even if inbreeding is locally active, is likely to support metapopulation maintenance and rapid recovery of local populations. In Kitsunezaki, however, genetic exchange among local populations is limited within few 100 m, and the metapopulation structure will decline in the long term because of inbreeding depression. Local dispersal distance of zoospores was investigated based on parent–offspring analysis in the Kitsunezaki population, which revealed that zoospores mainly settled within 5 m of their parent. However, some zoospores traveled over 27 m within the 4 × 30 m study area. The present study shows the importance of examination at different spatial scales when investigating zoospore dispersal of laminarialean kelps. [ABSTRACT FROM AUTHOR]

We implement a population genetics approach to clarify the role that temporal and environmental variability, spatially distinct locations and different hosts may have in the epidemiology of a plant disease and in the microevolution of its causative pathogen. In California and southern Oregon (USA), the introduction of the invasive pathogen Phytophthora ramorum, causal agent of the widespread disease Sudden Oak Death (SOD), has resulted in extensive mortality of various oaks Quercus sp. and of tanoak Notholithocarpus densiflorus. Although the disease can infect over a hundred hosts, California bay laurel Umbellularia californica is the most competent transmissive host but is not lethally affected by the disease. Using population genetics data, we identify the relationship among P. ramorum populations in bay laurels, oaks and tanoaks to clarify the contribution of each host on the epidemiology of SOD and on the microevolution of its causal agent and to explore differences in population structure across sites and years. We conclude that bay laurel is the primary source for infections of both tanoak and oak, and that tanoak contributes minimally to oak infection but can infect bay laurel, creating a secondary pathogen amplification process. Overall, pathogen diversity is associated with rainfall and presence of bay laurels, which sustain the largest populations of the pathogen. Additionally, we clarify that while bay laurels are a common source of inoculum, oaks and tanoaks act as sinks that maintain host‐specific pathogen genotypes not observed in bay laurel populations. Finally, we conclude that different sites support a dominance of different pathogen genotypes. Some genotypes were widespread, while others were limited to a subset of the plots. Sites with higher bay laurel densities sustained a higher genotypic diversity of the pathogen. This work provides novel insight into the ecology and evolutionary trajectories of SOD epidemics in natural ecosystems. [ABSTRACT FROM AUTHOR]

A fundamental goal in population genetics is to understand how variation is arrayed over natural landscapes. From first principles we know that common features such as heterogeneous population densities and barriers to dispersal should shape genetic variation over space, however there are few tools currently available that can deal with these ubiquitous complexities. Geographically referenced single nucleotide polymorphism (SNP) data are increasingly accessible, presenting an opportunity to study genetic variation across geographic space in myriad species. We present a new inference method that uses geo‐referenced SNPs and a deep neural network to estimate spatially heterogeneous maps of population density and dispersal rate. Our neural network trains on simulated input and output pairings, where the input consists of genotypes and sampling locations generated from a continuous space population genetic simulator, and the output is a map of the true demographic parameters. We benchmark our tool against existing methods and discuss qualitative differences between the different approaches; in particular, our program is unique because it infers the magnitude of both dispersal and density as well as their variation over the landscape, and it does so using SNP data. Similar methods are constrained to estimating relative migration rates, or require identity‐by‐descent blocks as input. We applied our tool to empirical data from North American grey wolves, for which it estimated mostly reasonable demographic parameters, but was affected by incomplete spatial sampling. Genetic based methods like ours complement other, direct methods for estimating past and present demography, and we believe will serve as valuable tools for applications in conservation, ecology and evolutionary biology. An open source software package implementing our method is available from https://github.com/kr‐colab/mapNN. [ABSTRACT FROM AUTHOR]

High‐density genotyping methods have revolutionized the field of population and conservation genetics in the past decade. To exploit the technological and analytical advances in the field, access to high‐quality genetic material is a key component. However, access to such samples in endangered and rare animals is often challenging or even impossible. Here, we used a minimally invasive sampling method (MIS) in the endangered cave salamander Proteus anguinus, the olm, to generate thousands of genetic markers using ddRADseq for population and conservation genomic analyses. Using tail clips and MIS skin swabs taken from the same individual, we investigated genotyping data properties of the two different sampling types. We found that sufficient DNA can be extracted from swab samples to generate up to 200,000 polymorphic SNPs in divergent Proteus lineages. Swab and tissue samples were highly reproducible exhibiting low SNP genotyping error rates. We found that SNPs were most frequently (~50%) located within genic regions, while the rest mapped to mostly flanking regions of repetitive DNA. The vast majority of DNA recovered from swabbing was host DNA. However, a fraction of DNA recovered from swabs contained additional ecological information on the species, including eDNA from the surrounding environment and bacterial skin fauna. Most exogenous DNA recovered from swabs were bacteria (~80%), followed by vertebrates (~20%). Our results demonstrate that MIS can be used to (i) generate tens of thousands of ddRADseq markers for conservation and population genomic analyses and (ii) inform on the species health status and ecology from exogenous DNA. [ABSTRACT FROM AUTHOR]

Winter flounder Pseudopleuronectes americanus (Walbaum 1792) are a coastal flatfish species of economic and cultural importance that have dwindled to <15, % of their historic abundance in the southern New England/Mid‐Atlantic region of the United States, with evidence indicating near‐extirpation of certain local populations. This species exhibits intricate behaviors in spawning and migration that contribute to population complexity and resilience. These behaviors encompass full or partial philopatry to natal estuaries, the generation of multiple pulses of larval delivery, and partial migration. The patterns of genetic diversity within and among estuaries and cohorts presented here carry important implications in understanding the susceptibility to demographic shocks, even if the full extent of genetic diversity within and among winter flounder stocks on the US East Coast remains unresolved. Our findings reveal connectivity between estuaries in Long Island, New York, suggesting the potential for genetic rescue of depleted subpopulations. Family reconstruction and relatedness analysis indicate that split cohorts and migration contingents are not the result of genetically distinct lineages. We found no evidence for genetic structure separating these groups, and in some instances, we were able to detect closely related individuals that belonged to different migratory contingents or cohorts. Characterizing the spatial and behavioral organization of this species at the population level is crucial for comprehending its potential for recovery, not only in terms of biomass but also in reinstating the complex population structure that supports resilience. The search for generality in winter flounder spawning and migration behavior remains elusive, but perhaps the lack of generalities within this species is what has allowed it to persist in the face of decades of environmental and anthropogenic stressors. [ABSTRACT FROM AUTHOR]

Conservation breeding programs are an effective approach to addressing biodiversity loss. Captive populations are managed to maintain genetic diversity, yet there remains an "implementation gap" in effectively translating molecular genetic data into management. Technological advancements are facilitating rapid generation of genetic data, increasing accessibility for breeding programs. In 2010, Frankham and colleagues proposed a six‐stage process for establishing successful conservation breeding and release programs. Here, we describe the conservation breeding program for the critically endangered Bellinger River turtle (Myuchelys georgesi) and characterize the value of genetic sampling for informing management actions. By generating a chromosome‐level genome and population genetic data, we investigated past and present diversity and assessed relatedness among captive founders. We present a framework modeled on Frankham and colleagues six stages to assist managers in implementing genetic data into actionable conservation strategies. This framework, and worked case study, for managers aims to better guide implementation of genetic approaches into conservation breeding programs. [ABSTRACT FROM AUTHOR]

In flowering plants, pollinators contribute to gene flow while they also respond to variation in plant traits together determined by genetic, epigenetic and environmental sources of variation. Consequently, a correlation between abundance and diversity of pollinators and the genetic and epigenetic characteristics of plant populations such as diversity or distinctiveness is expected. However, no study has explored these long‐term dimensions of plant–pollinator interactions. Mediterranean narrow endemics often exhibit unexpectedly high levels of population genetic and epigenetic diversity. We hypothesize that pollinators may contribute to explain this pattern. Specifically, given the higher sensitivity of small, isolated population to gene flow, we expect a stronger association of pollinators with population genetic and epigenetic variability in narrow endemics than in widely distributed congeners. We studied five pairs of congeneric plant species, consisting of one narrow endemic with a restricted distribution and one widespread congener, found in the Sierra de Cazorla mountains (SE Spain). We characterized the pollinators in up to three populations per species to estimate their diversity and visitation rates. Additionally, we calculated the genetic and epigenetic diversity and distinctiveness of each population using AFLP markers and methylation‐sensitive AFLP markers (MSAP), respectively. We assessed the relationship between pollinator diversity and visitation rates. The diversity of pollinators did not vary according to the plant´s distribution range, but visitation rate was higher in widespread species. As predicted, only narrow endemics showed a significant association between pollinators and their population genetic and epigenetic characteristics. Specifically, higher pollinator diversity and visitation rates entailed higher population genetic diversity and lower epigenetic distinctiveness. This work shows the importance of investigating the relationship between pollinator diversity and population genetics and epigenetics to better understand the evolution of plant rarity. [ABSTRACT FROM AUTHOR]

Whole genome sequences (WGS) of 185 North American Thoroughbred horses were compared to quantify the number and frequency of variants, diversity of mitotypes, and autosomal runs of homozygosity (ROH). Of the samples, 82 horses were born between 1965 and 1986 (Group 1); the remaining 103, selected to maximize pedigree diversity, were born between 2000 and 2020 (Group 2). Over 14.3 million autosomal variants were identified with 4.5–5.0 million found per horse. Mitochondrial sequences associated the North American Thoroughbreds with 9 of 17 clades previously identified among diverse breeds. Individual coefficients of inbreeding, estimated from ROH, averaged 0.266 (Group 1) and 0.283 (Group 2). When SNP arrays were simulated using subsets of WGS markers, the arrays over-estimated lengths of ROH. WGS-based estimates of inbreeding were highly correlated (r > 0.98) with SNP array-based estimates, but only moderately correlated (r = 0.40) with inbreeding based on 5-generation pedigrees. On average, Group 1 horses had more heterozygous variants (P < 0.001), more total variants (P < 0.001), and lower individual inbreeding (FROH; P < 0.001) than horses in Group 2. However, the distribution of numbers of variants, allele frequency, and extent of ROH overlapped among all horses such that it was not possible to identify the group of origin of any single horse using these measures. Consequently, the Thoroughbred population would be better monitored by investigating changes in specific variants, rather than relying on broad measures of diversity. The WGS for these 185 horses is publicly available for comparison to other populations and as a foundation for modeling changes in population structure, breeding practices, or the appearance of deleterious variants. [ABSTRACT FROM AUTHOR]

The Deccan mahseer, Tor khudree (Sykes 1839), belonging to family Cyprinidae is an important food and a game fish distributed in peninsular India. Due to overfishing and habitat destruction, the species is declared endangered and placed on the IUCN red list. Therefore, a well-designed conservation program may be essential to get this species protected in its natural habitat. We used a total of 152 samples from four rivers of peninsular India to assess the genetic diversity and structure of the mahseer using concatenated sequences of two mitochondrial genes, ATPase 6/8 (790 bp) and Cyt b (1000 bp). High haplotypic diversity was seen with 44 haplotypes. Individual gene wise haplotypes included 10 and 21 haplotypes for ATPase6/8 and Cyt b, respectively. AMOVA revealed most of the genetic variations (71.02%) to be within the populations. Significant genetic differentiation was observed between all population pairs, with FST values ranging from 0.121 to 0.372, with minimum between Tunga and Tungabhadra population and maximum between Tunga and Periyar population. Haplotype network showed one ancestral haplotype (TKACH04). Significant negative Fu's F and unimodal mismatch distribution suggested recent demographic expansion. The results of the present study would serve as a useful resource for further research on population genetics and conservation programs of the species. [ABSTRACT FROM AUTHOR]

We introduce a multi-allele Wright–Fisher model with mutation and selection such that allele frequencies at a single locus are traced by the path of a hybrid jump–diffusion process. The state space of the process is given by the vertices and edges of a topological graph, i.e. edges are unit intervals. Vertices represent monomorphic population states and positions on the edges mark the biallelic proportions of ancestral and derived alleles during polymorphic segments. In this setting, mutations can only occur at monomorphic loci. We derive the stationary distribution in mutation–selection–drift equilibrium and obtain the expected allele frequency spectrum under large population size scaling. For the extended model with multiple independent loci we derive rigorous upper bounds for a wide class of associated measures of genetic variation. Within this framework we present mathematically precise arguments to conclude that the presence of directional selection reduces the magnitude of genetic variation, as constrained by the bounds for neutral evolution. [ABSTRACT FROM AUTHOR]

We introduce a modified spatial Λ -Fleming–Viot process to model the ancestry of individuals in a population occupying a continuous spatial habitat divided into two areas by a sharp discontinuity of the dispersal rate and effective population density. We derive an analytical formula for the expected number of shared haplotype segments between two individuals depending on their sampling locations. This formula involves the transition density of a skew diffusion which appears as a scaling limit of the ancestral lineages of individuals in this model. We then show that this formula can be used to infer the dispersal parameters and the effective population density of both regions, using a composite likelihood approach, and we demonstrate the efficiency of this method on a range of simulated data sets. [ABSTRACT FROM AUTHOR]

Between 1925 and 1930, 11 or 12 non‐native mountain goats (Oreamnos americanus) were translocated from Alaska and British Columbia to the foothills of the Olympic Range. By 1970, descendants of these goats had colonized the entire range and concerns about the management of this introduced species developed as damage to alpine soil and vegetation occurred. A series of removals reduced the population from 1175 in 1983 to 389 by 1990, eventually growing to 584 in 2016. We used demographic and genetic data to parameterize a population genetics individual‐based simulation model of the Olympic Range mountain goats. We calibrated the model to replicate the population trajectory for Olympic mountain goats from establishment in the 1920s through the 1983 first census. As expected, modeled population dynamics from 1928 to 1983 mimicked parameter initialization from expanding populations. However, simulated heterozygosity did not align with observations, suggesting a process not accounted for within the simulation model, such as a bottleneck or founder effect. Sensitivity analyses showed changes in annual reproductive rate, juvenile mortality, and adult female mortality influencing population trajectories, but variation in male mortality revealed no changes. Evaluating the population dynamics of the model after removals showed that approximately 80% of the total animals removed during the 1980s needed to be female in order for the observed population estimates to occur. This model has the potential to be used more widely with established or introduced mountain goat populations, as well as to provide an approach for studying other introduced species and their population dynamics. [ABSTRACT FROM AUTHOR]

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Turkey oak (Quercus cerris L.) is one of the most ecologically and economically significant deciduous tree species in the Central and Southeast European regions. The species has long been known to exhibit high levels of genetic and phenotypic variation. Recent climate response predictions for Turkey oak suggest a significant distribution extension in Europe under climate change. Since Turkey oak has relative drought-tolerant behaviour, it is regarded as a potential alternative for other forest tree species during forestry climate adaptation efforts, not only in its native regions but also in Western Europe. For this reason, the survey of existing genetic variability, genetic resources, and adaptability of this species has great significance. Next-generation sequencing approaches, such as ddRAD-seq (Double digest restriction-site associated DNA sequencing), allow the attainment of high-resolution genome-wide single nucleotide polymorphisms (SNPs). This study provides the first highly variable genome-wide SNP data for Turkey oak generated by ddRAD-seq. The dataset comprises 17 607 de novo and 26 059 reference mapped SNPs for 88 individuals from eight populations, two from Bulgaria, one from Kosovo, and five from Hungary. Reference mapping was carried out by using cork oak's (Quercus suber L.) reference genome. The obtained high-resolution genome-wide markers are suitable for investigating selection and local adaptation and inferring genetic diversity, differentiation, and population structure. The dataset is accessible at: https://doi.org/10.5281/zenodo.8091252 [ABSTRACT FROM AUTHOR]

We investigated population genetics of the native tree species Acer velutinum Boiss., Fagus orientalis Lipsky, and Quercus castaneifolia C.A. Mey. in the Hyrcanian forests of northern Iran and also F. orientalis populations in the Euro-Siberian and Colchic subregions of northern Türkiye. We used the double-digest RADseq method and genotyped 90 populations and 1,589 individuals across the distribution range of the species. Genome-wide SNPs from 28 populations of A. velutinum, 32 populations of F. orientalis, and 30 Q. castaneifolia revealed higher genetic differentiation among A. velutinum populations than among F. orientalis and Q. castaneifolia. The global FST value was lowest for F. orientalis populations and highest for A. velutinum populations, while the global FIS value was negative for A. velutinum. Demographic history analysis revealed a bottleneck during the last glacial period (11,500—115,000 Kya) for the A. velutinum populations with reduced effective population size (Ne). All three species show multiple bottlenecks and reduced Ne during the Quaternary. Pronounced genetic divergence among A. velutinum populations in the Hyrcanian forests compared to the other two species suggests cryptic speciation. Conversely, F. orientalis and Q. castaneifolia populations showed low levels of genetic structure, suggesting that species-specific factors, such as pollen production and pollination efficiency, may have influenced the genetic patterns within these species in similar environments. The nucleotide diversity of F. orientalis populations in Iran is negatively correlated with altitude (p = 0.046). In contrast, A. velutinum populations show a significant correlation between nucleotide diversity and longitude (p = 0.008). Furthermore, the F. orientalis populations from Türkiye showed a distinct west–east genetic structure and were highly diverged from the Iranian F. orientalis populations. [ABSTRACT FROM AUTHOR]

Knowledge of the genetic diversity and population structure of species can facilitate conservation and guide management programs. However, the type of molecular markers used can affect estimates of genetic divergence and population structure. Here three types of molecular markers were used to estimate the genetic diversity and population structure of Euterpe edulis, a palm endemic to the Atlantic Forest and economically and ecologically important. The objective was to estimate the parameters of genetic diversity and population structure for two other types of molecular markers (SNP and SilicoDArT) in addition to the commonly used one (SSR) to the species. We used single nucleotide polymorphism (SNP), SilicoDArT, and microsatellite (SSR) markers in 138 E. edulis individuals sampled from 15 sites. Euterpe edulis individuals were grouped into 11 clusters using SNPs and SilicoDArT and six groups using SSR data. The SNP and SilicoDArT data showed less divergence between the individuals within each cluster in comparison to the results derived from the SSR data. The probability of reassigning individuals to their cluster of origin revealed an average association with the original clusters was 0.92 for SNPs (n = 100), 0.71 for SSR (n = 8), and 0.99 for SilicoDArT (n = 445). The genetic divergence is high among sites using SNP markers, whereas SSRs showed the largest genetic divergence is found within each site. The overall heterozygosity values for each site in the eight SSR (He = 0.69; Ho = 0.59) markers were almost four times higher than those values inferred using SNPs (data 7833 SNP, He = 0.15; Ho = 0.13; data 100 SNP, He = 0.14; Ho = 0.12). Within each site, we found low inbreeding rates using both markers (SNP and SSR). In addition, population structure analysis identified two strongly supported geographical groups, one northern and one southern Brazilian Atlantic Forest group, for both markers. This study contributes to the understanding of the population genetics and population structure of E. edulis and may have important implications for its conservation. In addition, our results suggest that SNP and SilicoDArT markers are more effective for evaluating population structure, but SSR is more capable of detecting diversity among individuals for this species. [ABSTRACT FROM AUTHOR]

The raccoon roundworm (Baylisascaris procyonis), a gastrointestinal nematode parasite of the raccoon (Procyon lotor), is the causative agent of a zoonotic disease that can cause severe neurological sequelae and even fatal cases. The parasite is now established in Europe and, while not present in all raccoon populations, it is currently expanding its range. Understanding the geographic distribution of the roundworm is a necessity for public health. Here, we report the first detections of the raccoon roundworm from Luxembourg. We used genetic techniques to test whether the roundworm originated from a distinct introduction event or entered the country by natural dispersal. We detected two roundworms in a raccoon that was road-killed in Echternach, northeastern Luxembourg. Furthermore, in a wildlife rescue centre, roundworms were detected in the latrine of an enclosure containing seven raccoons. Using different genetic techniques, we showed the Echternach roundworms to originate from the nearest German population, while the rescue centre roundworms were genetically distinct. By genotyping the host from a roundworm DNA extract, we identified a raccoon originating from southwest Luxembourg as the host of at least one roundworm. Roundworms are thus colonising Luxembourg both by natural dispersal and from an introduced population. The (potential) hosts all originated from the local population, suggesting that imported/introduced roundworms have already spread to the local raccoon population. Authorities should act as though the parasite is already widespread in the country, raising awareness among the public and individuals with occupational contact with raccoons. [ABSTRACT FROM AUTHOR]

Turkey oak (Quercus cerris L.) is a deciduous tree species of the genus Quercus section Cerris (Fagaceae), widely distributed in Europe and Asia Minor. Throughout its vast distribution range, the species carries high phenotypic and genetic variability. Due to its high drought tolerance, Turkey oak may have great potential to be a key tree species in Central and Western Europe under climate change conditions. However, more detailed information on its phylogeny, phylogeography, phenotypic, and genetic variability is still needed for a more careful and reliable assessment of the species' adaptation potential. To this end, based on 41 reviewed articles, we collected detailed information to support the evaluation of Turkey oak's adaptation potential under climate change. In the reviewed articles, we observed a significantly lower number of genetic studies of the members of the section Cerris (especially the Euro-Mediterranean species) relative to the subgenus Quercus. We also identified research gaps with respect to the functional and population genetics of the species that should be addressed in the future. Nevertheless, the different evolutionary background and adaptation strategies of Turkey oak as compared to Central European white oaks, as well as its high phenotypic and genetic variability, may indeed represent a great potential for this species to support the climate adaptation of forestry in Central and Western Europe. [ABSTRACT FROM AUTHOR]

Background: The common cat tapeworm, Hydatigera taeniaeformis, is widely distributed across many regions of the world but its global genetic diversity, ecology, and other biological features are not fully understood. The predator-prey relationship of felids and rodents sustains the transmission in both sylvatic and synanthropic or urban settings. This study was carried out in three urban market centres in Tamale, Ghana to determine the prevalence of H. taeniaeformis infection in urban rats and characterise the local population genetics using the mitochondrial nad1 gene sequences. Methods: From January to May 2023, rats were captured and euthanized to identity and isolate the H. taeniaeformis metacestodes. The full mitochondrial nad1 gene was amplified, sequenced and used to characterise the cestode population. Results: In total 64/80 rats from the three market centres were found naturally infected with metacestodes of H. taeniaeformis. Averagely, infected rats harboured two cysts with one exceptional case of 25 cysts in one liver. Each cyst harboured one metacestode. The DNA sequences revealed four haplotypes in a star-like distribution network across the three market centres. All four haplotypes were found to be unique, clustered with H. taeniaeformis sensu stricto (s.s.) global isolates and had only marginal variation among themselves. Conclusion: This is the first account of the genetic variability within H. taeniaeformis in Ghana and would contribute to ongoing and future studies on African regional biogeographic distribution of the common cat tapeworm. [ABSTRACT FROM AUTHOR]

Background: The Persian walnut (Juglans regia), an economically vital species within the Juglandaceae family, has seen its mitochondrial genome sequenced and assembled in the current study using advanced Illumina and Nanopore sequencing technology. Results: The 1,007,576 bp mitogenome of J. regia consisted of three circular chromosomes with a 44.52% GC content encoding 39 PCGs, 47 tRNA, and five rRNA genes. Extensive repetitive sequences, including 320 SSRs, 512 interspersed, and 83 tandem repeats, were identified, contributing to genomic complexity. The protein-coding sequences (PCGs) favored A/T-ending codons, and the codon usage bias was primarily shaped by selective pressure. Intracellular gene transfer occurred among the mitogenome, chloroplast, and nuclear genomes. Comparative genomic analysis unveiled abundant structure and sequence variation among J. regia and related species. The results of selective pressure analysis indicated that most PCGs underwent purifying selection, whereas the atp4 and ccmB genes had experienced positive selection between many species pairs. In addition, the phylogenetic examination, grounded in mitochondrial genome data, precisely delineated the evolutionary and taxonomic relationships of J. regia and its relatives. We identified a total of 539 RNA editing sites, among which 288 were corroborated by transcriptome sequencing data. Furthermore, expression profiling under temperature stress highlighted the complex regulation pattern of 28 differently expressed PCGs, wherein NADH dehydrogenase and ATP synthase genes might be critical in the mitochondria response to cold stress. Conclusions: Our results provided valuable molecular resources for understanding the genetic characteristics of J. regia and offered novel perspectives for population genetics and evolutionary studies in Juglans and related woody species. [ABSTRACT FROM AUTHOR]

Background: The application of Uniform Manifold Approximation and Projection (UMAP) for dimensionality reduction and visualization has revolutionized the analysis of single-cell RNA expression and population genetics. However, its potential in single-cell DNA sequencing data analysis, particularly for visualizing gene mutation information, has not been fully explored. Results: We introduce Mugen-UMAP, a novel Python-based program that extends UMAP's utility to single-cell DNA sequencing data. This innovative tool provides a comprehensive pipeline for processing gene annotation files of single-cell somatic single-nucleotide variants and metadata to the visualization of UMAP projections for identifying clusters, along with various statistical analyses. Employing Mugen-UMAP, we analyzed whole-exome sequencing data from 365 single-cell samples across 12 non-small cell lung cancer (NSCLC) patients, revealing distinct clusters associated with histological subtypes of NSCLC. Moreover, to demonstrate the general utility of Mugen-UMAP, we applied the program to 9 additional single-cell WES datasets from various cancer types, uncovering interesting patterns of cell clusters that warrant further investigation. In summary, Mugen-UMAP provides a quick and effective visualization method to uncover cell cluster patterns based on the gene mutation information from single-cell DNA sequencing data. Conclusions: The application of Mugen-UMAP demonstrates its capacity to provide valuable insights into the visualization and interpretation of single-cell DNA sequencing data. Mugen-UMAP can be found at https://github.com/tengchn/Mugen-UMAP [ABSTRACT FROM AUTHOR]

Hybridization between rare and widespread species can result in loss of genetic integrity for the rarer species, which can have management and conservation implications. One rare species, Phlox hirsuta, is a serpentine endemic in northern California, and it frequently co‐occurs with a widespread congener, Phlox speciosa. Putative hybrids were recognized based on intermediate morphology, so the possibility of hybridization was explored using floral morphological and molecular data. Ninety‐eight individuals of P. hirsuta and P. speciosa were collected from each of three sites, and floral features were measured and compared. Eleven microsatellite loci were amplified for species and putative hybrids, and inter‐ and intraspecific genetic diversity and relationships were investigated with multiple methods. Variation in morphological and molecular data was recovered. Floral variation was greater for P. hirsuta than P. speciosa. Putative hybrids were genetically allied with P. speciosa, but two individuals of P. hirsuta were resolved to have genetic similarity with P. speciosa. While hybridization is possible between the species, it is uncommon and appears to be primarily unidirectional. The small number of recognized hybrids may be due to ineffective interspecific pollination, hybrids being less fit than parents, and/or small sample sizes. Reinforcement does not appear to play a role in secondary contact between species. Both microsatellite loci and floral morphology varied across the small geographic range of P. hirsuta, suggesting local differentiation and adaptation are possible over short distances. [ABSTRACT FROM AUTHOR]

Inbreeding depression, the reduced fitness of inbred relative to outbred individuals was described more than two centuries ago, long before the development of population genetics. Its impact is central to evolutionary ecology and the evolution of mating systems, in particular self-fertilization in hermaphrodites. In the first half of the 20th century, population genetics revealed a mechanism for inbreeding depression through homozygosity. Numerous theoretical studies have modeled inbreeding depression as a function of genetic architecture and analyzed how it varies with population selfing rates. A major concept in these models is purging, i.e., the purging of recessive deleterious mutations through inbreeding. Consequently, inbreeding depression is expected to decrease with increasing population selfing rates. Along with these theoretical studies, many experimental studies, particularly on plants, have measured inbreeding depression using experimental crosses or directly in the field. The results of these studies have revealed that the evolutionary ecology of inbreeding depression is difficult to capture and that empirical data do not exactly match model predictions, specifically purging efficacy. In addition, the lability of inbreeding depression in natural populations can qualitatively affect the selective role of inbreeding depression in the evolution of mating systems. Recently, several studies have demonstrated the role of epigenetics in shedding new light on the dynamics of inbreeding depression in natural populations. This review provides a general overview of the studies on inbreeding depression and how various angles can help capture its selective role in natural populations. [ABSTRACT FROM AUTHOR]

Dominance is a fundamental parameter in genetics, determining the dynamics of natural selection on deleterious and beneficial mutations, the patterns of genetic variation in natural populations, and the severity of inbreeding depression in a population. Despite this importance, dominance parameters remain poorly known, particularly in humans or other non-model organisms. A key reason for this lack of information about dominance is that it is extremely challenging to disentangle the selection coefficient (s) of a mutation from its dominance coefficient (h). Here, we explore dominance and selection parameters in humans by fitting models to the site frequency spectrum (SFS) for nonsynonymous mutations. When assuming a single dominance coefficient for all nonsynonymous mutations, we find that numerous h values can fit the data, so long as h is greater than ~0.15. Moreover, we also observe that theoretically-predicted models with a negative relationship between h and s can also fit the data well, including models with h = 0.05 for strongly deleterious mutations. Finally, we use our estimated dominance and selection parameters to inform simulations revisiting the question of whether the out-of-Africa bottleneck has led to differences in genetic load between African and non-African human populations. These simulations suggest that the relative burden of genetic load in non-African populations depends on the dominance model assumed, with slight increases for more weakly recessive models and slight decreases shown for more strongly recessive models. Moreover, these results also demonstrate that models of partially recessive nonsynonymous mutations can explain the observed severity of inbreeding depression in humans, bridging the gap between molecular population genetics and direct measures of fitness in humans. Our work represents a comprehensive assessment of dominance and deleterious variation in humans, with implications for parameterizing models of deleterious variation in humans and other mammalian species. Author summary: The dominance coefficient (h) of a mutation determines its impact on organismal fitness when heterozygous. For instance, fully recessive mutations (h = 0) have no effects on fitness when heterozygous whereas additive mutations (h = 0.5) have an effect that is intermediate to the two homozygous genotypes. The extent to which deleterious mutations may be recessive, additive, or dominant is a key area of study in evolutionary genetics. However, dominance parameters remain poorly known in humans and most other organisms due to a variety of technical challenges. In this study, we aim to constrain the possible set of dominance and selection parameters for amino acid changing mutations in humans. We find that a wide range of models are possible, including models with a theoretically-predicted relationship between h and s. We then use a range of plausible selection and dominance models to explore how deleterious variation may have been shaped by the out-of-Africa bottleneck in humans. Our results highlight the subtle influence of dominance on patterns of genetic load in humans and demonstrate that models of partially recessive mutations at amino-acid-changing sites can explain the observed effects of inbreeding on mortality in humans. [ABSTRACT FROM AUTHOR]