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The purpose of this study was to explore primary care sports medicine physicians' comfort, competence, education, and scope of training in caring for transgender and gender nonconforming (TGNC) patients/athletes.Mixed-methods, cross-sectional survey.Online.In total, 4300 e-mails were successfully sent with 252 eligible responses received from the American Medical Society for Sports Medicine members.Previous relationships with TGNC persons; previous relationships with TGNC patients/athletes; frequency of care for TGNC patients/athletes.The participants completed a 38-item tool used to assess perceived comfort and competence treating TGNC patients/athletes. Physicians defined "transgender" and described their thoughts on unfair competitive advantage of transgender athletes.Most participants had worked with a TGNC patient (70.2%, n = 177), but far fewer worked with a TGNC athlete (n = 26.6%, n = 67). Among the participants who provided a definition of transgender (n = 183), only 28.4% (n = 52) of participants were able to correctly define the term, whereas most were able to partially (57.9%, n = 106) characterize the term. The most common mechanisms identified for learning about TGNC patients were reading peer-reviewed journal articles (44.8%, n = 113) and CME (41.3%, n = 104). Those with previous TGNC friend/family, patient, and athlete relationships had a significantly different level of comfort and competence treating TGNC patients/athletes.Previous care relationships with TGNC strongly influences comfort and perceived competence of primary care sports medicine physicians. Training, from unbiased peer-reviewed sources of data, is critical to improve care for TGNC patients/athletes.

Species distribution models (SDMs) are widely used to predict range shifts but could be unreliable under climate change scenarios because they do not account for evolution. The thermal physiology of a species is a key determinant of its range and thus incorporating thermal trait evolution into SDMs might be expected to alter projected ranges. We identified a genetic basis for physiological and behavioural traits that evolve in response to temperature change in natural populations of threespine stickleback (Gasterosteus aculeatus). Using these data, we created geographical range projections using a mechanistic niche area approach under two climate change scenarios. Under both scenarios, trait data were either static ("no evolution" models), allowed to evolve at observed evolutionary rates ("evolution" models) or allowed to evolve at a rate of evolution scaled by the trait variance that is explained by quantitative trait loci (QTL; "scaled evolution" models). We show that incorporating these traits and their evolution substantially altered the projected ranges for a widespread panmictic marine population, with over 7-fold increases in area under climate change projections when traits are allowed to evolve. Evolution-informed SDMs should improve the precision of forecasting range dynamics under climate change, and aid in their application to management and the protection of biodiversity.

Humans use their peripheral vision during locomotion to perceive an approaching obstacle in their path, while also focusing central gaze on steps ahead of them. However, certain physiological and psychological factors may change this strategy, such as when a walker is physically fatigued. In this study, 21 healthy participants walked through a dark room while wearing eye tracking glasses before and following intense exercise. Obstacles were placed in random locations along their path and became illuminated when participants approached them. Results indicate that, when fatigued, participants had altered spatial gaze strategies, including more frequent use of central gaze to perceive obstacles and an increased gaze angular displacement. However, there were no changes in temporal gaze strategies following exercise. These findings reveal how physical fatigue alters one’s visual perception of their environment during locomotion, and may partially explain why people are at greater risk of trips and falls while fatigued.

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.

Phenotypic plasticity is predicted to permit persistence in new environments, and may subsequently evolve to enhance fitness. Colonizing environments with lower winter temperatures can lead to the evolution of lower critical thermal minima; the corresponding physiological traits associated with temperature tolerance are predicted to involve mitochondrial function. Threespine stickleback (Gasterosteus aculeatus) have colonized freshwater lakes along the Pacific Northwest. These freshwater populations are known to exhibit cold-induced increases in mitochondrial volume density in pectoral muscle, but whether such plasticity evolved before or after colonization is uncertain. Here, we measure critical thermal minima (CTmin) in one marine and one freshwater population of threespine stickleback, and mitochondrial volume density in pectoral and cardiac tissue of both populations acclimated to different temperature treatments (6.2, 14.5 and 20.6 ℃). Mitochondrial volume density increased with cold acclimation in pectoral muscle; cardiac muscle was non-plastic but had elevated mitochondrial volume densities compared to pectoral muscle across all temperature treatments. There were no differences in the levels of plasticity between marine and freshwater stickleback, but neither were there differences in CTmin. Importantly, marine stickleback exhibited plasticity under low-salinity conditions, suggesting that marine stickleback had at least one necessary phenotype for persistence in freshwater environments before colonization occurred.

Offspring of divorce are generally more vulnerable to negative mental health outcomes than counterparts of intact marriages. However, not all cases of divorce are equivalent. The present study aime...

In the stickleback family (Gasterosteidae), divergence in pelvic morphology is typically associated with reproductive isolation and ecological niche specialization. In this study, we assessed whether reproductive isolation may be involved in the persistence of within-lake polymorphism in brook stickleback (Culaea inconstans (Kirtland, 1840)). We studied populations of brook stickleback in central Alberta, Canada, that are polymorphic for pelvic reduction (i.e., presence–absence of pelvic spines). We investigated the persistence of the pelvic polymorphisms over 40 generations in five lakes. We found that, of the five populations examined, the frequencies of pelvic phenotypes have remained unchanged in three populations, the polymorphism has persisted with significantly changed frequencies of pelvic phenotypes in one population, and the polymorphism has been lost in one population. Using 10 microsatellite loci, we observed low genetic divergence between individuals with and without pelvic spines in one lake, suggesting a lack of assortative mating among individuals with divergent pelvic phenotypes. This observation suggests that the pelvic polymorphism in brook stickleback persists due to balancing selection in the absence of reproductive isolation, although the selective forces were not evaluated. The significant changes in phenotypic frequencies in two populations are likely associated with environmental disturbances such as species introductions.

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 (

BACKGROUND Firefighters must complete a physical ability test to assess work readiness. There is a lack of understanding of how personal protective clothing (PPC) affects functional performance tests for work readiness, e.g. Triple Hop for Distance (THD) and Triple Hop for Work (THW). OBJECTIVE To examine firefighter PPC's effect on the THD and THW measures. METHODS Thirty-one healthy, untrained participants (male = 20, female = 11; age = 23±3 years; height = 175.30± 11.12 cm; mass = 77.94±14.24 kg; mass in PPC = 89.14±14.68 kg) completed three successful trials of the THD on their dominant and non-dominant leg, with and without PPC. The main outcome measures included maximum and mean distances on the THD with and without PPC and THW. RESULTS We identified a significant decrease in THD measures (mean difference = 97.83 cm; p < 0.001) and THW measures (mean difference = -326.61J; p < 0.001) when donning PPC in the dominant leg. We identified a significant decrease in THD (mean difference = 121.48 cm; p < 0.001) and THW (mean difference = 493.15J; p < 0.001) for females, and a significant difference for THD (mean difference = 84.83 cm; p < 0.001) for males when donning PPC. CONCLUSIONS The addition of PPC decreased the THD and THW measures. The additional mass of the PPC required the more energy to move the same distance without the PPC.

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.

Phenotypic plasticity is predicted to permit persistence in new environments, and may subsequently evolve to enhance fitness. Colonizing environments with lower winter temperatures can lead to the evolution of lower critical thermal minima; the corresponding physiological traits associated with temperature tolerance are predicted to involve mitochondrial function. Threespine stickleback (Gasterosteus aculeatus) have colonized freshwater lakes along the Pacific Northwest. These freshwater populations are known to exhibit cold-induced increases in mitochondrial volume density in pectoral muscle, but whether such plasticity evolved before or after colonization is uncertain. Here, we measure critical thermal minima (CTmin) in one marine and one freshwater population of threespine stickleback, and mitochondrial volume density in pectoral and cardiac tissue of both populations acclimated to different temperature treatments (6.2, 14.5 and 20.6 ℃). Mitochondrial volume density increased with cold acclimation in pectoral muscle; cardiac muscle was non-plastic but had elevated mitochondrial volume densities compared to pectoral muscle across all temperature treatments. There were no differences in the levels of plasticity between marine and freshwater stickleback, but neither were there differences in CTmin. Importantly, marine stickleback exhibited plasticity under low-salinity conditions, suggesting that marine stickleback had at least one necessary phenotype for persistence in freshwater environments before colonization occurred.

Rapidly changing environments pose unique challenges to the resident organisms. Tidepools in coastal environments vary in biophysical characteristics spatially and temporally, and how they vary determines their short- and long-term suitability as habitats and therefore influence on the distributions of tidepool organisms. Biophysical effects on distribution could differ between age classes, depending on their intrinsic ontogenetic requirements and dominance relations. In this study, we investigate the influence of physical pool characteristics on the site fidelity and population distribution of tidepool sculpin (Oligocottus maculosus Girard, 1856). We assessed short-term recapture of marked individuals and size-class distribution among four pool sets. The proportion of adults varied between pools primarily in association with water temperature and pool volume. Smaller adult and larger juvenile fish occupied warmer, small-volume pools, whereas larger adults occupied larger, cooler pools. Between 24% and 56% of marked fish were recaptured, with a higher probability of recapture in pools with “smooth” basins than in those with more rugose basins. Few fish moved among study pools, but the proportion of adults declined with repeated sampling, suggesting greater pool fidelity of juveniles. These results illustrate that intrinsic habitat features influence age- and size-class distributions in a resident tidepool sculpin species, with corresponding consequences for site fidelity.

Walleye (Sander vitreus) are in demand as a commercially and recreationally harvested freshwater fish in Canada. Managed populations may exhibit different phenotypic and genetic signatures from their natural counterparts. In Alberta, Canada, this fishery is recovering from population collapses attributed to intensive recreational angling. We hypothesized that historical population collapses would be associated with signatures of reduced genetic diversity. To address this question, we sampled six walleye lakes in northern Alberta, including historical tissue samples for one population, and used genotyping-by-sequencing to characterize 1081 single nucleotide polymorphisms (SNPs). Lakes were identified as unique genetic clusters except for two lakes that unexpectedly exhibited signs of genetic clustering. Using historical DNA samples, 428 homologous SNPs characterized in walleye between pre- and postpopulation collapse exhibited significant reductions in multiple estimates of genetic diversity. Collectively, our results illustrate that genotype-by-sequencing methods that integrate historical and contemporary samples in association with managed populations provide insight into the consequences of harvest pressure causing collapse.

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.

Coastal marine Gasterosteus aculeatus were captured from seven locations along the Pacific coast of North America, ranging across 21·8° latitude to test Jordan's rule, i.e. that vertebral number should increase with increasing latitude for related populations of fish. Vertebral number significantly increased with increasing latitude for both total and caudal vertebral number. Increasing length with latitude (sensu Bergmann's rule) was also supported, but the predictions for Jordan's rule held when controlling for standard length. Pleomerism was weakly evidenced. Gasterosteus aculeatus exhibited sexual dimorphism for Jordan's rule, with both sexes having more vertebrae at higher latitudes, but only males showing a positive association between latitude and the ratio of caudal to abdominal vertebrae. The number of dorsal- and anal-fin rays and basals increased with increasing latitude, while pectoral-fin ray number decreased. This study reinforces the association between phenotypic variation and environmental variation in marine populations of G. aculeatus.

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.

The molecular mechanisms underlying behavioural evolution following colonization of novel environments are largely unknown. Molecules that interact to control equilibrium within an organism form physiological regulatory networks. It is essential to determine whether particular components of physiological regulatory networks evolve or if the network as a whole is affected in populations diverging in behavioural responses, as this may affect the nature, amplitude and number of impacted traits. We studied the regulation of four physiological regulatory networks in freshwater and marine populations of threespine stickleback raised in a common environment, which were previously characterized as showing evolutionary divergence in behaviour and stress reactivity. We measured nineteen components of these networks (ligands and receptors) using mRNA and monoamine levels in the brain, pituitary and interrenal gland, as well as hormone levels. Freshwater fish showed higher expression in the brain of adrenergic (adrb2a), serotonergic (htr2a) and dopaminergic (DRD2) receptors, but lower expression of the htr2b receptor. Freshwater fish also showed higher expression of the mc2r receptor of the glucocorticoid axis in the interrenals. Collectively, our results suggest that the inheritance of the regulation of these networks may be implicated in the evolution of behaviour and stress reactivity in association with population divergence. Our results also suggest that evolutionary change in freshwater threespine stickleback may be more associated with the expression of specific receptors rather than with global changes of all the measured constituents of the physiological regulatory networks.

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