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ContextThe United States transgender patient population often suffers from insufficient health care and faces barriers to obtaining health care. Understanding the current classroom education provided in professional athletic training programs related to patient-centered and transgender patient care is necessary to foster improvements to the education of future health care providers.ObjectiveTo explore the education, comfort, and experience of professional athletic training students and program directors (PDs) on patient-centered care (PCC) and transgender patient care.DesignCross-sectional survey.SettingOnline survey.Patients or Other ParticipantsA total of 74 PDs of Commission on Accreditation of Athletic Training Education-accredited professional athletic training programs (age = 46 ± 9 years) and 452 athletic training students (age = 23 ± 3 years) responded to the survey.Data Collection and AnalysisTwo surveys were created from literature and were reviewed by a committee of content experts. Participants were sent links to their respective survey in March 2020. Surveys contained questions on demographic information, PCC, and transgender patient care. Data were analyzed descriptively with follow-up χ2 analyses comparing athletic training students' comfort and competence between those who learned and did not learn about transgender patient care.ResultsMost PDs reportedly felt comfortable (98.6%, n = 73) and competent (94.6%, n = 70) teaching PCC. Half (50% n = 37/74) of PDs include transgender health care in their program's curriculum but lacked competence (37.8%, n = 28) in teaching. All students felt comfortable (100%, n = 452) and competent (98.7%, n = 446) practicing PCC, but only 12.4% (n = 54) reported practicing it during clinical education. Less than half (43.1%, n = 195/452) of students learned about transgender patient care, yet most (78.3%, n = 354) felt comfortable but lacked competence (41.8% n = 189).ConclusionsFew students reportedly practice PCC during clinical education. Both groups perceived deficiencies in competence related to transgender patient care. We suggest PDs teach transgender health care in their curriculum and seek professional development to create meaningful educational experiences.

Understanding the drivers of successful species invasions is important for conserving native biodiversity and for mitigating the economic impacts of introduced species. However, whole-genome resolution investigations of the underlying contributions of neutral and adaptive genetic variation in successful introductions are rare. Increased propagule pressure should result in greater neutral genetic variation, while environmental differences should elicit selective pressures on introduced populations, leading to adaptive differentiation. We investigated neutral and adaptive variation among nine introduced brook trout (

Context Lesbian, gay, bisexual, transgender, and queer (LGBTQ) athletic trainers (ATs) face uncertain acceptance in the workplace. Objective To examine the perceptions of National Collegiate Athletic Association (NCAA) student-athletes toward ATs who identified as LGBTQ. Design Cross-sectional design. Setting Web-based survey. Patients or Other Participants A total of 623 (males = 212, females = 403, other = 8; age = 19.7 ± 1.4 years) NCAA student-athletes completed the survey. Main Outcome Measure(s) Participants completed a 19-item survey to assess their perceptions about the appropriateness of, quality of care from, and comfort with ATs who identified as LGBTQ. We asked 10 demographic questions and 2 questions regarding the student-athlete's exposure to individuals who identified as LGBTQ. Five matrix questions had 5 stems each to represent LGBTQ individuals on a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree) and 2 open-ended questions elicited qualitative data. We analyzed characteristics of central tendency to evaluate the level of appropriateness, quality of care, and level of comfort perceived by student-athletes of ATs who identified as LGBTQ. We used Mann-Whitney U and Kruskal-Wallis tests for post hoc analyses where appropriate. We used grounded theory to identify themes in the answers to the open-ended questions. Results Participants indicated they would seek health care and would feel comfortable approaching an AT who identified as LGBTQ. Participants agreed it was appropriate for an LGBTQ AT to work with both male and female sports and did not agree that health care provided by heterosexual and LGBTQ ATs differed. The open-ended responses revealed 4 themes: professionalism, upbringing, situational concerns, and concerns about specific populations that affected their perceptions. Conclusions In general, the NCAA student-athletes had positive perceptions of ATs who identified as LGBTQ.

Context Research suggests that patients who identify as lesbian, gay, bisexual, transgender, or queer (LGBTQ) are at risk for certain conditions and denied equal access to health care in physician offices compared with their heterosexual counterparts. However, little evidence exists regarding the treatment of LGBTQ student-athlete patients in the athletic training clinic and the role the athletic trainer (AT) plays in these health care experiences. Objective To explore the perceptions of ATs treating LGBTQ student-athlete patients. Design Cross-sectional study. Setting Web-based survey. Patients or Other Participants A total of 1077 collegiate and university ATs completed the survey (5685 e-mails distributed, 1214 surveys started, access rate = 21.4%, completion rate = 88.7%). Main Outcome Measure(s) Demographic information and level of agreement in 3 areas (approach, quality of care, and comfort) were obtained on a 5-point Likert scale. We asked ATs their likeliness of providing guidance to student-athletes about navigating their sexuality generally and as it related to athletic participation, if they thought they provided equal health care to a student-athlete who identified as LGBTQ, how comfortable they were treating LGBTQ student-athlete patients, and how comfortable they thought student-athlete patients would be seeking care from them or from providers in their clinic. Results Overall, we found differences among groups for sexual orientation, gender, religion, and the existence of interpersonal contact with LGBTQ friends or family for approach, quality of care, and comfort. We also identified 2 main themes indicating ATs' desire for more training and education, specifically in caring for transgender student-athletes and providing patient-centered care with professionalism, regardless of gender identity or sexual orientation. Conclusions Although differences existed among demographic groups, ATs had a generally positive view of treating LGBTQ student-athlete patients and wanted more training and education on the specific needs of this population.

The objective of this study was to examine the predictive value of the Triple Hop for Distance (THD) physical performance test to assess lower extremity (LE) strength and power in individuals donning firefighter personal protective equipment (PPE). Thirty-one healthy participants completed the THD in firefighter PPE on both the dominant and non-dominant limb. Dependent variables included LE power (vertical jump height [cm]) on a jump mat, and LE strength of the quadriceps and hamstrings (peak torque [Nm]) on an isokinetic dynamometer. THD was a strong predictor of LE power on the dominant (p

Eastern (Vireo gilvus gilvus) and western (V. g. swainsoni) forms of the Warbling Vireo have essentially allopatric breeding ranges across north-central North America, but come into contact in central Alberta, Canada. In 1986, Jon Barlow presented preliminary morphological and song evidence suggesting that the Warbling Vireo complex might comprise more than one valid species. However, to date, Barlow’s suggestion is supported by only limited DNA evidence, demonstration of molt and migration differences between the taxa, and anecdotal accounts of differences in song, morphology, plumage, and ecology. We analyzed variation in both mitochondrial and nuclear DNA in birds from Alberta and surrounding areas to determine the levels of genetic differentiation and hybridization occurring in the contact zone, and whether the two taxa warrant recognition as separate biological species. Our analyses reveal that Warbling Vireos in Alberta and the surrounding areas are separated into two well-defined, genetically differentiated, and monophyletic clades corresponding to previously recognized taxonomic groups. The two taxa come into contact in a narrow (~85 km) zone in Barrhead County, northwest of Edmonton, Alberta. They show evidence of limited hybridization. The distinct genetic differences are maintained in the contact zone, where individuals of the two taxa may occupy neighboring territories. Differences in spring arrival dates, molt schedules, and migration routes indicate that a migratory divide may play an important role in reproductive isolation. We suggest that the two taxa are distinct cryptic species: an eastern form, Vireo gilvus, and a western form, Vireo swainsoni.

Epigenetic mechanisms underlying phenotypic change are hypothesized to contribute to population persistence and adaptation in the face of environmental change. To date, few studies have explored the heritability of intergenerationally stable methylation levels in natural populations, and little is known about the relative contribution of cis- and trans-regulatory changes to methylation variation. Here, we explore the heritability of DNA methylation, and conduct methylation quantitative trait loci (meQTL) analysis to investigate the genetic architecture underlying methylation variation between marine and freshwater ecotypes of threespine stickleback (Gasterosteus aculeatus). We quantitatively measured genome-wide DNA methylation in fin tissue using reduced representation bisulfite sequencing of F1 and F2 crosses, and their marine and freshwater source populations. We identified cytosines (CpG sites) that exhibited stable methylation levels across generations. We found that genetic variance explained an average of 24 to 35% of the methylation variance, with a number of CpG sites possibly autonomous from genetic control. Finally, we detected both cis- and trans-meQTLs, with only trans-meQTLs overlapping with previously identified genomic regions of high differentiation between marine and freshwater ecotypes, as well as identified the genetic architecture underlying two key CpG sites that were differentially methylated between ecotypes. These findings demonstrate a potential role for DNA methylation in facilitating adaptation to divergent environments and improve our understanding of the heritable basis of population epigenomic variation.

Epigenetic mechanisms underlying phenotypic change are hypothesized to contribute to population persistence and adaptation in the face of environmental change. To date, few studies have explored the heritability of intergenerationally stable methylation levels in natural populations, and little is known about the relative contribution of cis- and trans-regulatory changes to methylation variation. Here, we explore the heritability of DNA methylation, and conduct methylation quantitative trait loci (meQTLs) analysis to investigate the genetic architecture underlying methylation variation between marine and freshwater ecotypes of threespine stickleback (Gasterosteus aculeatus). We quantitatively measured genome-wide DNA methylation in fin tissue using reduced representation bisulfite sequencing of F1 and F2 crosses, and their marine and freshwater source populations. We identified cytosines (CpG sites) that exhibited stable methylation levels across generations. We found that additive genetic variance explained an average of 24–35% of the methylation variance, with a number of CpG sites possibly autonomous from genetic control. We also detected both cis- and trans-meQTLs, with only trans-meQTLs overlapping with previously identified genomic regions of high differentiation between marine and freshwater ecotypes. Finally, we identified the genetic architecture underlying two key CpG sites that were differentially methylated between ecotypes. These findings demonstrate a potential role for DNA methylation in facilitating adaptation to divergent environments and improve our understanding of the heritable basis of population epigenomic variation.

The most remarkable feature of our planet is the diversity of its life forms, ranging from viruses and nanobacteria to blue whales and giant sequoias to satanic leaf‐tailed geckos and leafy seadragons (look them up!). Life is found in essentially all environments on earth, and the number of species living on our planet is many times greater than we could have imagined a century ago. A well‐regarded estimate pegs the number of eukaryotic species on earth at 8.7 million (±1.3 million), of which fewer than 15% are currently described (Mora et al., 2011). The diversity of prokaryotes is less clear (and highly controversial), but an analysis of 1.6 billion 16S ribosomal RNA sequences estimated that 0.8–1.6 million prokaryotic operational taxonomic units exist globally (Louca et al., 2019). While we do not know how many species are currently extant, or have existed in the past, we do know that this biodiversity is valuable, providing food, fibre and medicine, furnishing ecosystem services such as water and air purification, nutrient cycling, pollination and carbon uptake, and contributing to technological innovations ranging from biotechnology to robotics to material science. Moreover, biodiversity underlies the cultural identity of human populations and is important to human health and well‐being. Geographically, species richness increases from the Polar Regions to the tropics in terrestrial and surface marine ecosystems. Thus, some countries, especially those in tropical and subtropical regions, are endowed with much greater biodiversity than others. Unfortunately, benefits arising from the access and utilization of this biodiversity have been unequally shared, with (paradoxically) biodiversity‐poor countries often accruing the lion's share of economic gains. There can be imbalances within countries as well, wherein some segments of the population obtain greater economic benefits from biodiversity and associated traditional knowledge than indigenous peoples. The “Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization,” which came into force in 2014, is an international agreement designed to ensure that the benefits arising from biodiversity are shared equitably (https://www.cbd.int/abs/). However, few scientific journals require compliance with the Nagoya Protocol or the reporting of benefits from biodiversity research. In this editorial, we (the editors of Molecular Ecology and Molecular Ecology Resources) express support for the Nagoya Protocol and the principle of benefit sharing. We believe that scientific journals publishing research on biodiversity can play an important role in implementing the Nagoya Protocol and in reporting on benefits generated from such research. Below, we provide background on the Nagoya Protocol, discuss the kinds of benefits that may arise from biodiversity research, describe the rationale for reporting on these benefits and introduce changes to the journals’ Data Accessibility Statements to incorporate the requirements and goals of the Nagoya Protocol.

A challenge of modern ecological genomics is reducing uncertainty surrounding the biological inferences from gene expression. For example, approximately 40% of proteins in eukaryotic model organisms do not contain characterized domains (Gollery et al., 2006). Even proteins of "known function" are typically only characterized in the sense that they have a domain function, but provide no information on their biological role within the cell (e.g., activation, pathways or targets). Yet, as molecular ecologists, a common objective is to elucidate how organisms respond to environmental variation through changes in gene expression, including homoeostatic, acclimatory, and adaptive responses to environmental stressors, a challenge increased by poor protein ecological annotation. Now, in this issue of Molecular Ecology, Orsini et al. (2017) use the quintessential Daphnia system to characterize the differences in stress response in three genotypic backgrounds to common biotic and abiotic stressors found in nature. Using an optimized weighted gene co-expression network analysis, they link genes of unknown function to genes that they co-activate with and enrich for gene ontology. Determining the functional networks of genes that behave in genotype- and treatment-specific responses gives insight into possible pathways and respective ecological roles, helping pave the way for the next generation of transcriptomic studies in molecular ecology.

Populations in upstream versus downstream river locations can be exposed to vastly different environmental and ecological conditions and can thus harbor different genetic resources due to selection and neutral processes. An interesting question is how upstream–downstream directionality in rivers affects the evolution of immune response genes. We used next‐generation amplicon sequencing to identify eight alleles of the major histocompatibility complex (MHC) class II β exon 2 in the cyprinid longnose dace (Rhinichthys cataractae) from three rivers in Alberta, upstream and downstream of municipal and agricultural areas along contaminant gradients. We used these data to test for directional and balancing selection on the MHC. We also genotyped microsatellite loci to examine neutral population processes in this system. We found evidence for balancing selection on the MHC in the form of increased nonsynonymous variation relative to neutral expectations, and selection occurred at more amino acid residues upstream than downstream in two rivers. We found this pattern despite no population structure or isolation by distance, based on microsatellite data, at these sites. Overall, our results suggest that MHC evolution is driven by upstream–downstream directionality in fish inhabiting this system.

Investigating the consequences of landscape features on population genetic patterns is increasingly important to elucidate the ecological factors governing connectivity between populations and predicting the evolutionary consequences of landscapes. Small prairie lakes in Alberta, Canada, and the brook stickleback (Culaea inconstans) that inhabit them, provide a unique aquatic system whereby populations are highly isolated from one another. These heterogeneous and extreme environments are prone to winterkills, an event whereby most of the fish die and frequent bottlenecks occur. In this study, we characterized the genetic population structure of brook stickleback among several lakes, finding that the species is hierarchically influenced by within-lake characteristics in small-scale watersheds. Landscape genetic analyses of the role of spatial features found support for basin characteristics associated with genetic diversity and bottlenecks in 20% of the sampled lakes. These results suggest that brook stickleback population genetic patterns may be driven, at least in part, by ecological processes that accelerate genetic drift and landscape patterns associated with reduced dispersal. Collectively, these results reinforce the potential importance of connectivity in the maintenance of genetic diversity, especially in fragmented landscapes.

Environmental DNA (eDNA) applications are transforming the standard of characterizing aquatic biodiversity via the presence, location and abundance of DNA collected from environmental samples. As eDNA studies use DNA fragments as a proxy for the presence of organisms, the ecological properties of the complex and dynamic environments from which eDNA is sampled need to be considered for accurate biological interpretation. In this review, we discuss the role that differing environments play on the major processes that eDNA undergoes between organism and collection, including shedding, decay and transport. We focus on a mechanistic understanding of these processes and highlight how decay and transport models are being developed towards more accurate and robust predictions of the fate of eDNA. We conclude with five recommendations for eDNA researchers and practitioners, to advance current best practices, as well as to support a future model of eDNA spatio-temporal persistence.

The threespine stickleback (Gasterosteus aculeatus L., 1758) is a vertebrate model for the study of the relationship between phenotype and environment in facilitating rapid evolutionary change. Using four populations from a system of lakes in Katmai National Park and Preserve, Alaska, and microcomputed tomography and three-dimensional geometric morphometrics, we test the hypothesis that stickleback populations inhabiting freshwater environments display cranial phenotypes that are intermediate between the putative ancestral form and the low-plated freshwater populations that demonstrate substantial divergence toward new phenotypic optima. We further test the hypothesis that phenotypic covariance structure is disrupted in the context of such putatively recent adaptive events. We report significant phenotypic differences among all four populations that includes a component of sexual dimorphism. Furthermore, we show evidence of disrupted phenotypic covariance structure among these populations. Taken together, these findings indicate the importance of phenotypic quantification as a key step in elucidating both the ecological processes responsible for rapid adaptive radiations and the role of developmental mechanisms in biasing evolutionary change.

Body size is a highly variable trait among geographically separated populations. Size-assortative reproductive isolation has been linked to recent adaptive radiations of threespine stickleback (Gasterosteus aculeatus) into freshwater, but the genetic basis of the commonly found size difference between anadromous and derived lacustrine sticklebacks has not been tested. We studied the genetic basis of size differences between recently diverging stickleback lineages in southwest Alaska using a common environment experiment. We crossed stickleback within one anadromous (Naknek River) and one lake (Pringle Lake) population and between the anadromous and two lake populations (Pringle and JoJo Lakes), and raised them in a salinity of 4-6 ppt. The F1 anadromous and freshwater forms differed significantly in size, whereas hybrids were intermediate or exhibited dominance toward the anadromous form. Additionally, the size of freshwater F1s differed from their wild counterparts, with within-population F1s from Pringle Lake growing larger than their wild counterparts, while there was no size difference between lab-raised and wild anadromous fish. Sexual dimorphism was always present in anadromous fish, but not in freshwater, and not always in the hybrid crosses. These results, along with parallel changes among anadromous and freshwater forms in other regions, suggest that this heritable trait is both plastic and may be under divergent and/or sexual selection.

Ecological impacts of contaminants on population patterns in wild fish are impacted by many contaminants that readily enter aquatic systems. Responses to toxicants by individuals in lab studies generally do not predict population level consequences in natural systems. Trace levels of contaminants are present in all major rivers in southern Alberta, Canada, with concentrations higher down-stream of anthropogenic inputs like agricultural land-use and inputs of municipal wastewater effluents. Longnose dace (Rhinichthys cataractae) were used as a sentinel species to study field-based population-level responses to contaminants. We hypothesized that biomarker activity, triggered by contaminant exposure, should increase downstream of anthropogenic inputs in two southern Alberta rivers, with corresponding relations between biomarker activity and sex ratios, after accounting for age structure. Liver detoxification (ethoxyresorufin-O-deethylase activity = EROD) measured at reference and exposed sites on each river differed significantly in only the Bow River system. Sex ratios varied more downstream of anthropogenic inputs than upstream, but the direction of sex ratio bias was inconsistent and temporally dynamic. Sex ratios correlated with liver detoxification in only the Bow River. Taken together, these results suggest that contaminants alter sex ratios in long-nose dace, but that there is variation in anthropogenic stressors among rivers.

Genome-wide heterozygosity has long been hypothesized to play a role in buffering organisms against developmental perturbations, potentially resulting in increased symmetry. If true, this could in part explain the maintenance of standing genetic variation in wild populations. Marine threespine sticklebacks (Gasterosteus aculeatus) were sampled across their eastern Pacific coastal distribution from Alaska to California and variations in asymmetry for both structural and nonstructural armor traits (lateral plates) were assessed. Structural plates consistently showed less asymmetry than nonstructural plates, but standardized measures of heterozygosity were not correlated with the extent of asymmetry expressed by a fish. Fish that were heterozygous for the major-effect gene controlling lateral plate variation (Ectodysplasin) had higher occurrences of asymmetry, even when the individuals were phenotypically fully plated. Collectively, this suggests that heterozygosity at a major-effect locus can have a greater impact on asymmetry than heterozygosity sampled across the genome.

Fishing is a popular and lucrative sport around the world and, in some cases, may contribute to declining fish stocks. To mediate this problem and maintain fish biomass in aquatic ecosystems, catch-and-release fishing, whereby a fish is caught and immediately released, has been implemented in many countries. It is unclear whether the injuries to the mouth that are caused by the hook have an impact on feeding performance of fishes. Using high-speed video and computational fluid dynamics (CFD), we asked whether injuries around the mouth caused by fishing hooks have a negative impact on suction feeding performance (measured as maximum prey velocity) of the commonly angled marine shiner perch (

Fishing is a popular and lucrative sport around the world and, in some cases, may contribute to declining fish stocks. To mediate this problem and maintain fish biomass in aquatic ecosystems, catch-and-release fishing, whereby a fish is caught and immediately released, has been implemented in many countries. It is unclear whether the injuries to the mouth that are caused by the hook have an impact on feeding performance of fishes. Using high-speed video and computational fluid dynamics (CFD), we asked whether injuries around the mouth caused by fishing hooks have a negative impact on suction feeding performance (measured as maximum prey velocity) of the commonly angled marine shiner perch (Cymatogaster aggregata). We hypothesized that fish with mouth injuries would exhibit decreased feeding performance compared with controls. Ten shiner perch were caught using scientific angling and 10 were caught using a seine net. Feeding events were then recorded at 500 frames per second using a high-speed camera. Compared with the control group, maximum prey velocity was significantly lower in the injured group (P

The tight fit between form and function in organisms suggests the influence of adaptive evolution in biomechanics; however, the prevalence of adaptive traits, the mechanisms by which they arise and the corresponding responses to selection are subjects of extensive debate. We used three-dimensional microcomputed tomography and geometric morphometrics to characterize the structure of phenotypic covariance within the G. aculeatus trophic apparatus and its supporting structures in wild and controlled crosses of fish from two different localities. Our results reveal that while the structure of phenotypic covariance is conserved in marine and freshwater forms, it may be disrupted in the progeny of artificial crosses or during rapid adaptive divergence events. We discuss these results within the context of integrating covariance structure with quantitative genetics, toward establishing predictive links between genes, development, biomechanics, and the environment.

Degraded DNA from suboptimal field sampling is common in molecular ecology. However, its impact on techniques that use restriction site associated next-generation DNA sequencing (RADSeq, GBS) is unknown. We experimentally examined the effects of in situDNA degradation on data generation for a modified double-digest RADSeq approach (3RAD). We generated libraries using genomic DNA serially extracted from the muscle tissue of 8 individual lake whitefish (Coregonus clupeaformis) following 0-, 12-, 48- and 96-h incubation at room temperature posteuthanasia. This treatment of the tissue resulted in input DNA that ranged in quality from nearly intact to highly sheared. All samples were sequenced as a multiplexed pool on an Illumina MiSeq. Libraries created from low to moderately degraded DNA (12-48 h) performed well. In contrast, the number of RADtags per individual, number of variable sites, and percentage of identical RADtags retained were all dramatically reduced when libraries were made using highly degraded DNA (96-h group). This reduction in performance was largely due to a significant and unexpected loss of raw reads as a result of poor quality scores. Our findings remained consistent after changes in restriction enzymes, modified fold coverage values (2- to 16-fold), and additional read-length trimming. We conclude that starting DNA quality is an important consideration for RADSeq; however, the approach remains robust until genomic DNA is extensively degraded.

Summary In epidemiological studies of wildlife parasites, faecal genotyping has been introduced to prevent bias in estimates of parasite prevalence from faecal samples collected in the field. Such an approach could be particularly relevant in the study of Echinococcus multilocularis transmission in urban settings, where estimates of prevalence and patterns of infection in wild canid hosts are key parameters used in zoonotic risk assessment and management. However, no previous study has evaluated the reliability of E. multilocularis faecal prevalence, and individual patterns of infection in definitive hosts remain poorly understood. We evaluated faecal genotyping as an epidemiological tool, using E. multilocularis in urban coyotes Canis latrans as our study system. Combining parasitological analysis and multilocus individual genotyping of coyote faeces, we compared faecal parasite prevalence with the prevalence obtained from genotyped faecal samples. Furthermore, we assessed patterns of individual infection, such as re-infection rates and phenology of parasite egg excretion. Of 425 faeces collected in five urban sites, we genotyped 142 samples (33·4%) corresponding to 60 unique individual coyotes. Number of genotyped samples per coyote ranged between 1 and 10 (mean = 2·3). Genotypes were obtained at 4–6 microsatellite loci and had a mean reliability of 0·9975. Faecal prevalence of E. multilocularis in genotyped coyotes was 25·0%, and similar to results previously obtained from non-genotyped faeces. Faecal genotyping allowed estimating a re-infection rate of individual coyotes of 57·1% and to observe temporal patterns of parasite infection that were not detected using non-genotyped faeces. Synthesis and applications. If compared to independent data obtained through coyote post-mortem examination, our results suggest that reliable estimates of overall parasite prevalence in definitive host populations can be efficiently obtained through well-designed field collection and traditional faecal parasitological analysis. However, faecal genotyping allows assessing the dynamics of individual infections, which could otherwise only be estimated by using invasive techniques. Combining faecal genotyping with parasitology has a great potential in assessing zoonotic risk transmission in urban areas, as well as advancing the field of wildlife ecology, disease ecology and conservation.

Life-history transitions have evolved repeatedly in numerous taxa, although the ecological and evolutionary conditions favouring such transitions in the presence of gene flow remain poorly understood. The present study aimed to disentangle the effects of isolation-by-distance and isolation-by-environment on genetic differentiation between two sympatric life-history ecotypes. Using 14 microsatellite loci, we first characterized amphidromous and freshwater groups of Cottus asper in a high gene flow setting in the Lower Fraser River system (south-western British Columbia, Canada) to test for the effects of habitat and geographical distance on the distribution of life-history ecotypes. Within the main river channel, no genetic differentiation was found, whereas tributaries even close to the estuary were genetically differentiated. Partial mantel tests confirmed that genetic differentiation between river tributaries and the main channel was independent from geographical distance, with distance-scaled migration rates indicating reduced gene flow from the main channel into the tributaries. Our results suggest that isolation-by-environment can play an important role for the early stage of life-history transitions, and may promote differentiation among life-history ecotypes despite the presence of gene flow. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 943–957.

SummaryThe role of natural selection in the maintenance of genetic variation in wild populations remains a major problem in evolution. The influence of disruptive natural selection on genetic variation is especially interesting because it might lead to the evolution of assortative mating or dominance [1, 2]. In theory, variation can persist at a gene under disruptive natural selection, but the process is little studied and there are few examples [3, 4]. We report a stable polymorphism in the bony armor of threespine stickleback maintained with a deficit of heterozygotes at the major underlying gene, Ectodysplasin (Eda) [5]. The deficit vanishes at the embryo life stage only to re-emerge in adults, indicating that disruptive natural selection, rather than nonrandom mating, is the cause. The mechanism enabling long-term persistence of the polymorphism is unknown, but disruptive selection is predicted to be frequency dependent, favoring homozygous genotypes when they become rare. Further research on the ecological and evolutionary processes affecting individual genes will ultimately lead to a better understanding of the causes of genetic variation in populations.

SummaryThe interplay between selection and genetic exchange at a color locus between populations of Timema walking sticks acts as an anti-speciation phenotype. This actively counteracts speciation and offers a general mechanism to explain the porous nature of species boundaries.

Most species evolve within fluctuating environments, and have developed adaptations to meet the challenges posed by environmental heterogeneity. One such adaptation is phenotypic plasticity, or the ability of a single genotype to produce multiple environmentally-induced phenotypes. Yet, not all plasticity is adaptive. Despite the renewed interest in adaptive phenotypic plasticity and its consequences for evolution, much less is known about maladaptive plasticity. However, maladaptive plasticity is likely an important driver of phenotypic similarity among populations living in different environments. This paper traces four strategies for overcoming maladaptive plasticity that result in phenotypic similarity, two of which involve genetic changes (standing genetic variation, genetic compensation) and two of which do not (standing epigenetic variation, plastic compensation). Plastic compensation is defined as adaptive plasticity overcoming maladaptive plasticity. In particular, plastic compensation may increase the likelihood of genetic compensation by facilitating population persistence. We provide key terms to disentangle these aspects of phenotypic plasticity and introduce examples to reinforce the potential importance of plastic compensation for understanding evolutionary change.

The discipline of molecular ecology has undergone enormous changes since the journal bearing its name was launched approximately two decades ago. The field has seen great strides in analytical methods development, made groundbreaking discoveries and experienced a revolution in genotyping technology. Here, we provide brief perspectives on the main subdisciplines of molecular ecology, describe key questions and goals, discuss common challenges, predict future research directions and suggest research priorities for the next 20 years., We thank the participants in the Molecular Ecology Symposium and Online Forum for many of the ideas put forward in this article.

Investigating the consequences of landscape features on population genetic patterns is increasingly important to elucidate the ecological factors governing connectivity between populations and predicting the evolutionary consequences of landscapes. Small prairie lakes in Alberta, Canada, and the brook stickleback (Culaea inconstans) that inhabit them, provide a unique aquatic system whereby populations are highly isolated from one another. These heterogeneous and extreme environments are prone to winterkills, an event whereby most of the fish die and frequent bottlenecks occur. In this study, we characterized the genetic population structure of brook stickleback among several lakes, finding that the species is hierarchically influenced by within‐lake characteristics in small‐scale watersheds. Landscape genetic analyses of the role of spatial features found support for basin characteristics associated with genetic diversity and bottlenecks in 20% of the sampled lakes. These results suggest that brook stickleback population genetic patterns may be driven, at least in part, by ecological processes that accelerate genetic drift and landscape patterns associated with reduced dispersal. Collectively, these results reinforce the potential importance of connectivity in the maintenance of genetic diversity, especially in fragmented landscapes.

Understanding the genomic basis of adaptive divergence in the presence of gene flow remains a major challenge in evolutionary biology. In prickly sculpin (Cottus asper), an abundant euryhaline fish in northwestern North America, high genetic connectivity among brackish-water (estuarine) and freshwater (tributary) habitats of coastal rivers does not preclude the build-up of neutral genetic differentiation and emergence of different life history strategies. Because these two habitats present different osmotic niches, we predicted high genetic differentiation at known teleost candidate genes underlying salinity tolerance and osmoregulation. We applied whole genome sequencing of pooled DNA samples (Pool-Seq) to explore adaptive divergence between two estuarine and two tributary habitats. Paired-end sequence reads were mapped against genomic contigs of European Cottus and the gene content of candidate regions was explored based on comparisons with the threespine stickleback genome. Genes showing signals of repeated differentiation among brackish-water and freshwater habitats included functions such as ion-transport and structural permeability in freshwater gills, which suggests that local adaptation to different osmotic niches might contribute to genomic divergence among habitats. Overall, the presence of both repeated and unique signatures of differentiation across many loci scattered throughout the genome is consistent with polygenic adaptation from standing genetic variation and locally variable selection pressures in the early stages of life history divergence. This article is protected by copyright. All rights reserved.

Speciation is a multifaceted process that involves numerous aspects of the biological sciences and occurs for multiple reasons. Ecology plays a major role, including both abiotic and biotic factors. Whether populations experience similar or divergent ecological environments, they often adapt to local conditions through divergence in biomechanical traits. We investigate the role of biomechanics in speciation using fish predator–prey interactions, a primary driver of fitness for both predators and prey. We highlight specific groups of fishes, or specific species, that have been particularly valuable for understanding these dynamic interactions and offer the best opportunities for future studies that link genetic architecture to biomechanics and reproductive isolation (RI). In addition to emphasizing the key biomechanical techniques that will be instrumental, we also propose that the movement towards linking biomechanics and speciation will include (i) establishing the genetic basis of biomechanical traits, (ii) testing whether similar and divergent selection lead to biomechanical divergence, and (iii) testing whether/how biomechanical traits affect RI. Future investigations that examine speciation through the lens of biomechanics will propel our understanding of this key process.

Thermal pollution from industrial processes can have negative impacts on the spawning and development of cold-water fish. Point sources of thermal effluent may need to be managed to avoid affecting discrete populations. Correspondingly, we examined fine-scale ecological and genetic population structure of two whitefish species (Coregonus clupeaformis and Prosopium cylindraceum) on Lake Huron, Canada, in the immediate vicinity of thermal effluent from nuclear power generation. Niche metrics using δ13C and δ15N stable isotopes showed high levels of overlap (48.6 to 94.5%) in resource use by adult fish captured in areas affected by thermal effluent compared to nearby reference locations. Isotopic niche size, a metric of resource use diversity, was 1.3- to 2.8-fold higher than reference values in some thermally affected areas, indicative of fish mixing. Microsatellite analyses of genetic population structure (Fst, STRUCTURE and DAPC) indicated that fish captured at all locations in the vicinity of the power plant were part of a larger population extending beyond the study area. In concert, ecological and genetic markers do not support the presence of an evolutionarily significant unit in the vicinity of the power plant. Thus, future research should focus on the potential impacts of thermal emissions on development and recruitment.

Despite recent progress, we still know relatively little about the genetic architecture that underlies adaptation to divergent environments. Determining whether the genetic architecture of phenotypic adaptation follows any predictable patterns requires data from a wide variety of species. However, in many organisms, genetic studies are hindered by the inability to perform genetic crosses in the laboratory or by long generation times. Admixture mapping is an approach that circumvents these issues by taking advantage of hybridization that occurs between populations or species in the wild. Here, we demonstrate the utility of admixture mapping in a naturally occurring hybrid population of threespine sticklebacks (Gasterosteus aculeatus) from Enos Lake, British Columbia. Until recently, this lake contained two species of sticklebacks adapted to divergent habitats within the lake. This benthic-limnetic species pair diverged in a number of phenotypes, including male nuptial coloration and body shape, which were previously shown to contribute to reproductive isolation between them. However, recent ecological disturbance has contributed to extensive hybridization between the species, and there is now a single, admixed population within Enos Lake. We collected over 500 males from Enos Lake and found that most had intermediate nuptial color and body shape. By genotyping males with nuptial color at the two extremes of the phenotypic distribution, we identified seven genomic regions on three chromosomes associated with divergence in male nuptial color. These genomic regions are also associated with variation in body shape, suggesting that tight linkage and/or pleiotropy facilitated adaptation to divergent environments in this benthic-limnetic species pairs.

Transition of an evolving population to a new adaptive optimum is predicted to leave a signature in the distribution of effect sizes of fixed mutations. If they affect many traits (are pleiotropic), large effect mutations should contribute more when a population evolves to a farther adaptive peak than to a nearer peak. We tested this prediction in wild threespine stickleback fish (Gasterosteus aculeatus) by comparing the estimated frequency of large effect genetic changes underlying evolution as the same ancestor adapted to two lake types since the end of the ice age. A higher frequency of large effect genetic changes (quantitative trait loci) contributed to adaptive evolution in populations that adapted to lakes representing a more distant optimum than to lakes in which the optimum phenotype was nearer to the ancestral state. Our results also indicate that pleiotropy, not just optimum overshoot, contributes to this difference. These results suggest that a series of adaptive improvements to a new environment leaves a detectable mark in the genome of wild populations. Although not all assumptions of the theory are likely met in natural systems, the prediction may be robust enough to the complexities of natural environments to be useful when forecasting adaptive responses to large environmental changes.

All-female 'species' of fish have been shown to be great models in ecological and evolutionary studies because of the insights they can provide into the origin and evolution of asexuality, the ecology of hybrids, associations between genotype and environment, and the maintenance of sex. Gynogenetic organisms that evolved from sexual ancestors, and combine the disadvantageous traits from sexuality and asexuality, have long baffled evolutionary biologists trying to understand their origin and persistence with their sympatric sexual counterparts. In this issue, a new study using an integrated molecular phylogenetic and classical genetic approach has uncovered compelling evidence regarding the obscure asexual origin of the Amazon molly, Poecilia formosa. By performing an extensive phylogeographic analysis, Stock et al. (2010) provide evidence that the Amazon molly arose only once within its history, with monophyly being strongly supported by mitochondrial DNA and microsatellite analyses. This result, combined with an elaborate failed attempt to resynthesize the lineage, suggests that vertebrate gynogens such as the Amazon molly are not rare because they are at a disadvantage to their sexual counterparts, but because the genomic conditions under which they arise are rare. Organisms that apparently combine the disadvantages of both sexuality and asexuality remain difficult to understand from both an ecological and an evolutionary perspective, and Stock et al. (2010) highlight several outstanding important questions. Nonetheless, given that we now have a better knowledge of the origin and history of this unique 'species', this should allow researchers to better understand how these frozen F1's can persist amidst the masterpiece of nature.

Ecological speciation is the process by which barriers to gene flow between populations evolve due to adaptive divergence via natural selection. A relatively unexplored area in ecological speciation is the role of gene expression. Gene expression may be associated with ecologically important phenotypes not evident from morphology and play a role during colonization of new environments. Here we review two potential roles of gene expression in ecological speciation: (1) its indirect role in facilitating population persistence and (2) its direct role in contributing to genetically based reproductive isolation. We find indirect evidence that gene expression facilitates population persistence, but direct tests are lacking. We also find clear examples of gene expression having effects on phenotypic traits and adaptive genetic divergence, but links to the evolution of reproductive isolation itself remain indirect. Gene expression during adaptive divergence seems to often involve complex genetic architectures controlled by gene networks, regulatory regions, and “eQTL hotspots.” Nonetheless, we review how approaches for isolating the functional mutations contributing to adaptive divergence are proving to be successful. The study of gene expression has promise for increasing our understanding ecological speciation, particularly when integrative approaches are applied.

Growing knowledge of the molecular basis of adaptation in wild populations is expanding the study of natural selection. We summarize ongoing efforts to infer three aspects of natural selection—mechanism, form and history—from the genetics of adaptive evolution in threespine stickleback that colonized freshwater after the last ice age. We tested a mechanism of selection for reduced bony armour in freshwater by tracking genotype and allele frequency changes at an underlying major locus (Ectodysplasin) in transplanted stickleback populations. We inferred disruptive selection on genotypes at the same locus in a population polymorphic for bony armour. Finally, we compared the distribution of phenotypic effect sizes of genes underlying changes in body shape with that predicted by models of adaptive peak shifts following colonization of freshwater. Studies of the effects of selection on genes complement efforts to identify the molecular basis of adaptive differences, and improve our understanding of phenotypic evolution.

Climate change is predicted to lead to increased average temperatures and greater intensity and frequency of high and low temperature extremes, but the evolutionary consequences for biological communities are not well understood. Studies of adaptive evolution of temperature tolerance have typically involved correlative analyses of natural populations or artificial selection experiments in the laboratory. Field experiments are required to provide estimates of the timing and strength of natural selection, enhance understanding of the genetics of adaptation and yield insights into the mechanisms driving evolutionary change. Here, we report the experimental evolution of cold tolerance in natural populations of threespine stickleback fish ( Gasterosteus aculeatus ). We show that freshwater sticklebacks are able to tolerate lower minimum temperatures than marine sticklebacks and that this difference is heritable. We transplanted marine sticklebacks to freshwater ponds and measured the rate of evolution after three generations in this environment. Cold tolerance evolved at a rate of 0.63 haldanes to a value 2.5°C lower than that of the ancestral population, matching values found in wild freshwater populations. Our results suggest that cold tolerance is under strong selection and that marine sticklebacks carry sufficient genetic variation to adapt to changes in temperature over remarkably short time scales.

In contrast to the large amount of ecological information supporting the role of natural selection as a main cause of population divergence and speciation, an understanding of the genomic basis underlying those processes is in its infancy. In this paper, we review the main findings of a long-term research programme that we have been conducting on the ecological genomics of sympatric forms of whitefish (Coregonusspp.) engaged in the process of speciation. We present this system as an example of how applying a combination of approaches under the conceptual framework of the theory of adaptive radiation has yielded substantial insight into evolutionary processes in a non-model species. We also discuss how the joint use of recent biotechnological developments will provide a powerful means to address issues raised by observations made to date. Namely, we present data illustrating the potential offered by combining next generation sequencing technologies with other genomic approaches to reveal the genomic bases of adaptive divergence and reproductive isolation. Given increasing access to these new genomic tools, we argue that non-model species studied in their ecological context such as whitefish will play an increasingly important role in generalizing knowledge of speciation.