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2,445 results for “Genetics: population”
Supplementary material 3 from: Patterson BD, Webala PW, Lavery TH, Agwanda BR, Goodman SM, Kerbis Peterhans JC, Demos TC (2020) Evolutionary relationships and population genetics of the Afrotropical leaf-nosed bats (Chiroptera, Hipposideridae). ZooKeys 929: 117-161. https://doi.org/10.3897/zookeys.929.50240
Figure S3. Phylogeny of Hipposideridae based on Bayesian inference analysis of cyt-b based on 452 individuals
Supplementary material 2 from: Patterson BD, Webala PW, Lavery TH, Agwanda BR, Goodman SM, Kerbis Peterhans JC, Demos TC (2020) Evolutionary relationships and population genetics of the Afrotropical leaf-nosed bats (Chiroptera, Hipposideridae). ZooKeys 929: 117-161. https://doi.org/10.3897/zookeys.929.50240
Figure S2. Phylogeny of Hipposideridae based on maximum likelihood analysis of cyt-b based on 452 individuals
Data from: Disease swamps molecular signatures of genetic-environmental associations to abiotic factors in Tasmanian devil (Sarcophilus harrisii) populations
Landscape genomics studies focus on identifying candidate genes under selection via spatial variation in abiotic environmental variables, but rarely by biotic factors such as disease. The Tasmanian devil (Sarcophilus harrisii) is found only on the environmentally heterogeneous island of Tasmania and is threatened with extinction by a nearly 100% fatal, transmissible cancer, devil facial tumor disease (DFTD). Devils persist in regions of long-term infection despite epidemiological model predictions of species' extinction, suggesting possible adaptation to DFTD. Here, we test the extent to which spatial variation and genetic diversity are associated with the abiotic environment and/or DFTD. We employ genetic-environment association analyses using a RAD-capture panel including 6,886 SNPs from 3,286 individuals sampled pre- and post-disease arrival. Pre-disease, we find significant correlations of allele frequencies with environmental variables, including 365 unique loci linked to 71 genes, suggesting local adaptation to abiotic environment. The majority of candidate loci detected pre-DFTD were not detected post disease arrival. Several post-DFTD candidate loci were associated with disease prevalence and were in linkage disequilibrium with genes involved in tumor suppression and immune response. Loss of apparent signal of abiotic local adaptation post-disease suggests swamping by the strong selection resulting from the rapid onset of DFTD.
Data from: Examination of the efficacy of small genetic panels in genomic conservation of companion animal populations
<p>In many ways dogs are an ideal model for the study of genetic erosion and population recovery, problems of major concern in the field of conservation genetics. Genetic diversity in many dog breeds has been declining systematically since the beginning of the 1800's, when modern breeding practices came into fashion. As such, inbreeding in domestic dog breeds is substantial and widespread and has led to an increase in recessive deleterious mutations of high effect as well as general inbreeding depression. Pedigrees can in theory be used to guide breeding decisions, though are often incomplete and do not reflect the full history of inbreeding. Small microsatellite panels are also used in some cases to choose mating pairs to produce litters with low levels of inbreeding. However, the long-term impact of such practices have not been thoroughly evaluated. Here, we use forward simulation on a model of the dog genome to examine the impact of using limited markers panels to guide pairwise mating decisions on genome-wide population level genetic diversity. Our results suggest that in unmanaged populations, where breeding decisions are made at the pairwise- rather than population-level, such panels can lead to accelerated loss of genetic diversity at genome regions unlinked to panel markers, compared to random mating. These results demonstrate the importance of genome-wide genetic panels for managing and conserving genetic diversity in dogs and other companion animals.</p>
Population genetic structure and demographic history of the lone star tick, Amblyomma americanum (Ixodida: Ixodidae): new evidence supporting old records
Range expansions are a potential outcome of climate change. Population genetic structure and demography can be used as tools to evaluate hypotheses on changes in geographic distribution. In this study we explored the genetic variability, population genetic structure, demographic history, and habitat suitability of Amblyomma americanum, a North American tick species that is a known vector of several pathogenic microorganisms. We used a novel double digestion restriction site-associated DNA sequencing (dd-RAD seq), and we discovered 8181 independent single nucleotide polymorphisms (SNPs) from 189 ticks from across the geographic range of the species. Overall, genetic diversity was lower than expected. Further, the edge populations did not have a statistically significant lower diversity than core populations, and hypotheses of range expansion are not supported by a test based on genetic data. Nonetheless, moderate levels of population structure were detected among geographic regions, with the northeast cluster the least variable. Demographic and species distribution models support a scenario where A. americanum was present in more northern locations in the past, underwent a bottleneck, and is now recovering. These findings highlight the importance of demographic modeling and genomic data in assessing the recent history and genetic structure of pathogen vectors.
Data from: Stage- and thermal-specific genetic architecture for preadult viability in natural populations of Drosophila melanogaster
Studying the processes affecting variation for preadult viability is essential to understand the evolutionary trajectories followed by natural populations. This task requires focusing on the complex nature of the phenotype-genotype relationship by taking into account usually neglected aspects of the phenotype and recognizing the modularity between different ontogenetic stages. Here we describe phenotypic variability for viability during the larval and pupal stages in lines derived from three natural populations of Drosophila melanogaster, as well as the variability for phenotypic plasticity and canalization at two different rearing temperatures. The observed phenotypic differences between populations can be attributed both to adaptation to environmental conditions and lack of gene flow between them. According to our results, different aspects of the phenotype (means, plasticity, canalization, plasticity of canalization) are affected by different genetic bases underlying changes in viability in a stage- and environment-specific manner. These findings explain the generalized maintenance of genetic variability for this fitness trait.
Data from: Friends and Family: a software program for identification of unrelated individuals from molecular marker data. And from: Genetic diversity, relatedness and inbreeding of ranched and fragmented Cape buffalo populations in southern Africa
The identification of related and unrelated individuals from molecular marker data is often difficult, particularly when no pedigree information is available and the data set is large. High levels of relatedness or inbreeding can influence genotype frequencies and thus genetic marker evaluation, as well as the accurate inference of hidden genetic structure. Identification of related and unrelated individuals is also important in breeding programmes, to inform decisions about breeding pairs and translocations. We present Friends and Family, a Windows executable program with a graphical user interface that identifies unrelated individuals from a pairwise relatedness matrix or table generated in programs such as COANCESTRY and GenAlEx. Friends and Family outputs a list of samples that are all unrelated to each other, based on a user-defined relatedness cut-off value. This unrelated data set can be used in downstream analyses, such as marker evaluation or inference of genetic structure. The results can be compared to that of the full data set to determine the effect related individuals have on the analyses. We demonstrate one of the applications of the program: how the removal of related individuals altered the Hardy-Weinberg equilibrium test outcome for microsatellite markers in an empirical data set. Friends and Family can be obtained from https://github.com/DeondeJager/Friends-and-Family.
Data from: Hidden genetic variance contributes to increase the short-term adaptive potential of selfing populations
Standing genetic variation is considered a major contributor to the adaptive potential of species. The low heritable genetic variation observed in self-fertilising populations has led to the hypothesis that species with this mating system would be less likely to adapt. However, a non-negligible amount of cryptic genetic variation for polygenic traits, accumulated through negative linkage disequilibrium, could prove to be an important source of standing variation in self-fertilising species. To test this hypothesis we simulated populations under stabilizing selection subjected to an environmental change. We demonstrate that, when the mutation rate is high (but realistic), selfing populations are better able to store genetic variance than outcrossing populations through genetic associations, notably due to the reduced effective recombination rate associated with predominant selfing. Following an environmental shift, this diversity can be partially remobilized, which increases the additive variance and adaptive potential of predominantly (but not completely) selfing populations. In such conditions, despite initially lower observed genetic variance, selfing populations adapt as readily as outcrossing ones within a few generations. For low mutation rates, purifying selection impedes the storage of diversity through genetic associations, in which case, as previously predicted, the lower genetic variance of selfing populations results in lower adaptability compared to their outcrossing counterparts. The population size and the mutation rate are the main parameters to consider, as they are the best predictors of the amount of stored diversity in selfing populations. Our results and their impact on our knowledge of adaptation under high selfing rates are discussed.
Data from: Temporal variation in spatial genetic structure during population outbreaks: distinguishing among different potential drivers of spatial synchrony
Spatial synchrony is a common characteristic of spatio-temporal population dynamics across many taxa. While it is known that both dispersal and spatially autocorrelated environmental variation (i.e., the Moran effect) can synchronize populations, the relative contributions of each, and how they interact, is generally unknown. Distinguishing these mechanisms and their effects on synchrony can help us to better understand spatial population dynamics, design conservation and management strategies, and predict climate change impacts. Population genetic data can be used to tease apart these two processes as the spatio-temporal genetic patterns they create are expected to be different. A challenge, however, is that genetic data are often collected at a single point in time, which may introduce context-specific bias. Spatio-temporal sampling strategies can be used to reduce bias and to improve our characterization of the drivers of spatial synchrony. Using spatio-temporal analyses of genotypic data, our objective was to identify the relative support for these two mechanisms to the spatial synchrony in population dynamics of the irruptive forest insect pest, the spruce budworm (Choristoneura fumiferana), in Quebec (Canada). AMOVA, cluster analysis, isolation by distance and sPCA were used to characterize spatio-temporal genomic variation using 1370 SBW larvae sampled over four years (2012-2015) and genotyped at 3,562 SNP loci. We found evidence of overall weak spatial genetic structure that decreased from 2012 to 2015 and a genetic diversity homogenization among the sites. We also found genetic evidence of a long-distance dispersal event over > 140 km. These results indicate that dispersal is the key mechanism involved in driving population synchrony of the outbreak. Early intervention management strategies that aim to control source populations have the potential to be effective through limiting dispersal. However, the timing of such interventions relative to outbreak progression is likely to influence their probability of success.
Data from: Genetic population structure and variation at phenology-related loci in anadromous Arctic char (Salvelinus alpinus)
The Arctic will be especially affected by climate change, resulting in altered seasonal timing. Anadromous Arctic char (Salvelinus alpinus) is strongly influenced by sea surface temperature (SST) delimiting time periods available for foraging in the sea. Recent studies of salmonid species have shown variation at phenology-related loci associated with timing of migration and spawning. We contrasted genetic population structure at 53 SNPs versus four phenology-related loci among 15 anadromous Arctic char populations from Western Greenland and three outgroup populations. Among anadromous populations, the time period available for foraging at sea (> 2oC) ranges from a few weeks to several months, motivating two research questions: 1) Is population structure compatible with possibilities for evolutionary rescue of anadromous populations during climate change? 2) Does selection associated with latitude or SST regimes act on phenology-related loci? In Western Greenland, strong isolation-by-distance at SNPs was observed and spatial autocorrelation analysis showed genetic patch size up to 450 km, documenting contingency and gene flow among populations. Outlier tests provided no evidence for selection at phenology-related loci. However, in Western Greenland, mean allele length at OtsClock1b was positively associated with the time of year when SST first exceeded 2oC and negatively associated with duration of the period where SST exceeded 2oC. This is consistent with local adaptation for making full use of the time period available for foraging in the sea. Current adaptation may become maladaptive under climate change, but long-distance connectivity of anadromous populations could redistribute adaptive variation across populations and lead to evolutionary rescue.
The impact of local population genetic background on the spread of the selfish element Medea-1 in red flour beetles
<p>Selfish genetic elements have been found in the genomes of many species, yet our understanding of their evolutionary dynamics is only partially understood. A number of distinct selfish <i>Medea</i> elements are naturally present in many populations of the red flour beetle (<i>Tribolium castaneum</i>). Although these <i>Medea</i> elements are predicted by models to increase in frequency within populations because any offspring of a <i>Medea</i>-bearing mother that do not inherit at least one <i>Medea</i> allele will die, experiments demonstrating an increase in a naturally occuring <i>Medea</i> element are lacking. Our survey of the specific <i>Medea </i>element<i>, </i>M<sup>1</sup>, in the United States showed that it had a patchy geographic distribution. From the survey it could not be determined if this distribution was caused by a slow process of M<sup>1</sup> colonization of discrete populations or if some populations lacked M<sup>1</sup> because they had genetic factors conferring resistance to the <i>Medea </i>mechanism. We show that populations with naturally low to intermediate M<sup>1</sup> frequencies likely represent transient states during the process of <i>Medea</i> spread. Furthermore, we find no evidence that genetic factors are excluding M<sup>1</sup> from US populations where the element is not presently found. We also show how a known suppressor of <i>Medea</i> can impair the increase of M<sup>1</sup> in populations and discuss the implications of our findings for pest-management applications of <i>Medea</i> elements.</p>
Genetic connectivity and population structure of African savanna elephants (Loxodonta africana) in Tanzania
<p>Increasing human population growth, exurban development, and associated habitat fragmentation is accelerating the isolation of many natural areas and wildlife populations across the planet. In Tanzania, rapid and ongoing habitat conversion to agriculture has severed many of the country's former wildlife corridors between protected areas. To identify historically-linked protected areas, we investigated the genetic structure and gene flow of African savanna elephants in Tanzania using microsatellite and mitochondrial DNA markers in 688 individuals. Our results indicate distinct population genetic structure within and between ecosystems across Tanzania, and reveal important priority areas for connectivity conservation. Elephants sampled from the Tarangire-Manyara ecosystem appear marginally, yet significantly isolated from elephants sampled from the greater Serengeti ecosystem (mean FST = 0.03), where two distinct subpopulations were identified.Unexpectedly, elephants in the Lake Manyara region appear to be more closely related to those across the East African Rift wall in the Ngorongoro Conservation Area than they are to the neighboring Tarangire subpopulations. We concluded that the Rift wall has had a negligible influence on genetic differentiation up to this point, but differentiation may accelerate in the future because of ongoing loss of corridors in the area. Interestingly, relatively high genetic similarity was found between elephants in Tarangire and Ruaha although they are separated by >400 km. In southern Tanzania, there was little evidence of female-mediated gene flow between Ruaha and Selous, probably due to the presence of the Udzungwa Mountains between them. Despite observing evidence of significant isolation, the populations of elephants we examined generally exhibited robust levels of allelic richness (mean AR = 9.96), heterozygosity (mean µHE = 0.73), and effective population sizes (mean Ne = 148). Our results may inform efforts to restore wildlife corridors between protected areas in Tanzania in order to facilitate gene flow for long-term survival of elephants and other species.</p>
Data from: Population genetic structures of two ecologically distinct species Betula platyphylla and B. ermanii inferred based on nuclear and chloroplast DNA markers
Climatic oscillations during the last glacial maximum (LGM) significantly affected the distribution patterns and genetic structure of extant plants. Northeast China (NEC) is a major biodiversity center in East Asia, and the influence of historical climate change on NEC populations is critical for understanding species responses to future climate change. However, only a few phylogeographic studies of cool-temperate deciduous tree species have been conducted in the area, and results are inconsistent for species with different niches or distribution areas. We employed multiple chloroplast and nuclear markers to investigate the genetic structure of two ecologically contrasting species, Betula platyphylla and B. ermanii, in NEC. Rare haplotypes were identified in the chloroplast genome of these species, and both exhibited high levels of nucleotide diversity based on a fragment of the nuclear gene G3PDH and microsatellites. Moreover, significant phylogeographic structure was detected for B. platyphylla, suggesting that these populations had recolonized from independent glacial refuges, whereas no genetic structure was found for B. ermanii.
Data from: Restricted connectivity and population genetic fragility in a globally endangered hammerhead shark
Vagile, large-bodied marine organisms frequently have wide range dispersion but also dependence on coastal habitats for part of their life-history. These characteristics may induce complex population genetic structure patterns, with resulting implications for the management of exploited populations. The scalloped hammerhead, Sphyrna lewini, is a cosmopolitan, migratory shark in tropical and warm temperate waters, inhabiting coastal bays during parturition and juvenile development and the open ocean as adults. Here, we investigated the genetic connectivity and diversity of S. lewini in the western Atlantic using large sample coverage (N=308), and data from whole mitochondrial control region (mtCR) sequences and ten nuclear microsatellite loci. We detected significant population genetic structure with both mtCR and microsatellites markers (mtCR: ΦST = 0.60; p < 0.001; microsatellites: Dest 0.0794, p = 0.001, FST = 0.046, p < 0.05), and isolation by distance (mtCR r = 0.363, p = 0.009; microsatellites r = 0.638, p = 0.007). The migration and gene flow patterns, based on mtCR and microsatellites were asymmetric, and female reproductive philopatry is postulated to explain such population subdivision patterns. The notable population differentiation at microsatellites markers indicates low-levels of male-mediated gene flow in the western Atlantic. The overall effective population size was estimated as 299 (215 – 412 Confidence Interval), and there was no evidence of strong or recent bottleneck effects. Findings of at least three management units, moderate genetic diversity, and low effective population size in the context of current overfishing calls for intensive management aimed at short and long-term conservation for this endangered species in the western Atlantic Ocean.
Data from: Wintering grounds, population size and evolutionary history of a cryptic passerine species from isotopic and genetic data
<p>Cryptic species pose a particular challenge to biologists in the context of life history investigations because of the difficulty in their field discrimination. Additionally, there is normally a lag in their widespread acceptance by the scientific community once they are formally recognised. These two factors might constrain our ability to properly assess the conservation status of the different species conforming a cryptic complex. In this study, we analysed isotopic and genetic data to shed light into the still unclear wintering grounds, population size and evolutionary history of the Iberian chiffchaff (<i>Phylloscopus ibericus</i>), a species included within the Common chiffchaff (<i>Phylloscopus collybita</i>) until two decades ago due to their phenotypic similarity. We used molecular methods to identify spring-migrating <i>Phylloscopus</i> species captured in northern Iberia, and by comparing the Hydrogen isotopic ratios of their claw tips (δ<sup>2</sup>H<sub>c</sub>; which would reflect the signatures of their wintering grounds), we detected that δ<sup>2</sup>H<sub>c</sub> values of Iberian chiffchaffs were similar to Willow warblers (<i>Phylloscopus trochilus</i>; a renowned trans-Saharan migrant), and higher than Common chiffchaffs (mostly a pre-Saharan migrant). These results strongly support the idea that Iberian chiffchaffs winter in tropical Africa. We additionally reconstructed the phylogeny and evolutionary history of the Iberian chiffchaff's clade using mitochondrial and nuclear markers. Our results revealed relatively high values of nucleotide diversity (and, hence, high N<sub>e</sub>) for the species that were greater than the values of the Common/Iberian most recent common ancestor. This suggests that the Iberian chiffchaff did not experience strong bottlenecks after diverging from the Common chiffchaff approximately one million years ago. Ultimately, our study provides another illustrative example of how isotopic and genetic analysis tools can help to enhance our understanding of avian ecology and evolution.</p>
Cryptic species and genetic connectivity among populations of the coral Pocillopora damicornis (Scleractinia) in the tropical southwestern Pacific
<p>Studying population genetic connectivity (i.e., identifying gene flow among populations and understanding their impacts on the genetic structure and diversity of populations) is first a matter of knowing what we work on, that is, accurately delimiting evolutionary units. Here, we focused on <em>Pocillopora damicornis</em> sensu stricto (or <em>Pocillopora </em>PSH04 sensu Gélin et al. in Mol Phylogenet Evol 109:430–446. http://dx.doi.org/10.1016/j.ympev.2017.01.018, 2017). From 458 colonies sampled within the tropical southwestern Pacific [Chesterfield Islands and New Caledonia (Grande Terre and Loyalty Islands)], Bayesian assignments and network analyses were conducted with 11-microsatellite loci to first evaluate the genetic partitioning of the colonies in distinct Secondary Species Hypotheses (SSHs), then in distinct clusters. Population genetic connectivity was then assessed for each cluster separately. <em>Pocillopora </em>PSH04 was partitioned into two highly differentiated SSHs (SSH04a and SSH04b), regularly found in sympatry. Furthermore, SSH04a was subdivided into two clusters (SSH04a-1 and SSH04a-2). This pattern of genetic structuring seems not related to clonality, but rather to the establishment of reproductive barriers. Nevertheless, considering each cluster separately, the populations appeared highly differentiated, suggesting relatively weak gene flow. This low connectivity among populations, coupled with the existence of cryptic species, brings new insights to the connectivity pattern of this understudied Pacific region.</p> <p>This dataset contains the microsatellite genotypes analysed (458 <em>Pocillopora</em> PSH04 colonies × 13 loci).</p>
Major inconsistencies of inferred population genetic structure estimated in a large set of domestic horse breeds using microsatellites
<p>STRUCTURE remains the most applied tool aimed at recovering the true, but unknown, population structure from observed microsatellite data or other genetic markers. About 30% of <span class="Program"><span>STRUCTURE</span></span>-based studies could not be reproduced (Gilbert et al., 2012). Here we use a large set of data from 2323 horses from 93 domestic breeds plus the Przewalski horse, typed at 15 microsatellite markers, to evaluate how program settings, in particular the so far insufficiently evaluated number of replicates, impact the estimation of the optimal number of population clusters <i>K</i><sub>opt</sub> that best describe the observed data. Domestic horses are suited as a test case as there is extensive knowledge of the history of many breeds, extensive phylogenetic analyses. Different methods based on different genetic assumptions and statistical procedures (<span class="Program"><span>DAPC</span></span>, <span class="Program"><span>FLOCK</span></span>, PCoA and <span class="Program"><span>STRUCTURE</span></span> with different run scenarios) all revealed the general, broad-scale relationships among the breeds that largely reflect known breed histories but diverged largely how they characterized small-scale patterns. <span class="Program"><span>STRUCTURE</span></span> failed to consistently identify <i>K</i><sub>opt</sub> using the most widespread approach, the ΔK method, despite very large numbers of MCMCs (3,000,000) and replicates (100). The interpretation of breed structure over increasing numbers of<i> K</i>, without assuming a <i>K</i><sub>opt</sub>, was consistent with known breed histories. The over-reliance on <i>K</i><sub>opt</sub> should be replaced by a qualitative description of clustering over increasing <i>K</i>, which is scientifically more honest and has the advantage of being much faster and less computer intensive as lower numbers of MCMC iterations and repetitions suffice for stable results. Very large data sets are highly challenging for cluster analyses, especially when populations with complex genetic histories are investigated.</p>
Comparative population genetics of the federally endangered Relict Darter, and its sister taxon the Clarks Darter (Teleostei: Percidae)
<p><span>The southeastern United States harbors one of the most diverse temperate freshwater fish faunas of the world. Unfortunately, due to improper land use practices and habitat degradation, many of the species in this region are imperiled and may become extinct without appropriate conservation efforts. This study examined the population dynamics of an endangered endemic darter of southwest Kentucky, the Relict Darter (</span><span>Etheostoma chienense</span><span>) and its sister taxon, the undescribed Clarks Darter (</span><span>Etheostoma </span><span>cf. </span><span>oophylax</span><span>). Mitochondrial sequence data coupled with SNP data were used to infer population structure, gene flow, genetic variation, and effective population sizes of both species. The results from this study, based on 160 individuals from nine localities, indicate that the endangered Relict Darter possesses limited genetic variation based on mitochondrial DNA haplotypes (N=4). In addition, SNP data (6.8k markers) further indicates limited genetic structure (K=1), as well as a low effective population size (143-918), suggesting that the Relict Darter can be managed as a single, panmictic conservation unit. It is suggested that conservation efforts be taken to protect remaining habitats, augment the system with artificial spawning substrates, and, as a last resort (if needed), supplement the natural population with captive reared individuals. </span><span>Ethesotoma </span><span>cf. </span><span>oophylax </span><span>showed some genetic variation among distant sites, but more samples are needed throughout the range in order to fully understand the population dynamics of this species.</span></p>
Parasite turnover zone at secondary contact: a new pattern in host-parasite population genetics
<p>We introduce a new pattern of population genetic structure in a host-parasite system that can arise after secondary contact of previously isolated populations. Due to different generation time and therefore different tempo of molecular evolution the host and parasite populations reach different degrees of genetic differentiation during their separation (e.g. in refugia). Consequently, during the secondary contact the host populations are able to re-establish a single panmictic population across the area of contact, while the parasite populations stop their dispersal at the secondary contact zone and create a narrow hybrid zone. From the host's perspective, the parasite's hybrid zone functions on a microevolutionary scale as a "parasite turnover zone": while the hosts are passing from area A to area B, their parasites turn genetically from the area A genotypes to the area B genotypes. We demonstrate this novel pattern on a model composed of <em>Apodemus</em> mice and <em>Polyplax</em> lice by comparing maternally inherited markers (complete mitochondrial genomes, and complete genomes of vertically transmitted symbiont <em>Legionella polyplacis</em>) with SNPs derived from the louse genomic data. We discuss circumstances that may lead to this pattern and possible reasons why it has been overlooked in the studies on host parasite population genetics.</p>
Data from: Chloroplast population genetics reveals low levels of genetic variation and conformation to the central–marginal hypothesis in Taxus wallichiana var. mairei, an endangered conifer endemic to China
The central–marginal hypothesis predicts that geographically peripheral populations should exhibit reduced genetic diversity and increased genetic differentiation than central populations due to smaller effective population size and stronger geographical isolation. We evaluated these predictions in the endangered conifer Taxus wallichiana var. mairei. Eight plastid simple sequence repeats (cpSSRs) were used to investigate plastid genetic variation in 22 populations of Taxus wallichiana var. mairei, encompassing nearly its entire distribution range. Low levels of plastid genetic variation and differentiation were detected in the populations, and the findings were attributed to low mutation rates, small population sizes, habitat fragmentation and isolation, and effective pollen or seed dispersal. Hunan and Hubei were identified as major refugia based on the number of private haplotypes and species distribution modeling. Trends in plastid genetic diversity and genetic differentiation from central to peripheral populations supported the predictions of the central–marginal hypothesis. In scenarios wherein the future climate becomes warmer, we predict that some peripheral populations will disappear and southern and southeastern regions will become significantly less habitable. Factors that include the levels of precipitation during the driest month, annual precipitation level, and annual temperature range will be decisive in shaping the future distribution of these populations. This study provides a theoretical basis for the conservation of T. wallichiana var. mairei.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.