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12,309 results for “America”
Data from: Genetic patterns across an invasion's history: a test of change versus stasis for the Eurasian round goby in North America
Biological invasions comprise accidental evolutionary experiments, whose genetic compositions underlie relative success, spread, and persistence in new habitats. However, little is known about whether, or how, their population genetic patterns change temporally and/or spatially across the invasion's history. Theory predicts that most would undergo founder effect, exhibit low genetic divergence across the new range, and gain variation over time via new arriving propagules. To test these predictions, we analyze population genetic diversity and divergence patterns of the Eurasian round goby Neogobius melanostomus across the two decades of its North American invasion in the Laurentian Great Lakes, comparing results from 13 nuclear DNA microsatellite loci and mitochondrial DNA cytochrome b sequences. We test whether "genetic stasis", "genetic replacement", and/or "genetic supplement" scenarios have occurred at the invasion's core and expansion sites, in comparison to its primary native source population in the Dnieper River, Black Sea. Results reveal pronounced genetic divergence across the exotic range, with population areas remaining genetically distinct and statistically consistent across two decades, supporting "genetic stasis" and "founder takes most". The original genotypes continue to predominate, whose high population growth likely outpaced the relative success of later arrivals. The original invasion core has stayed the most similar to the native source. Secondary expansion sites indicate slight allelic composition convergence towards the core population over time, attributable to some early "genetic supplementation". The geographic and temporal coverage of this investigation offers a rare opportunity to discern population dynamics over time and space in context of invasion genetic theory versus reality.
Data from: New Neogene taxa of the tribe Chlamydini Teppner, 1922 (Pectinidae, Bivalvia) of southern South America
The Chilean species traditionally assigned to the genera Chlamys Röding, 1798 or Zygochlamys Ihering, 1907 are now placed in two new endemic South American taxa: Dietotenhosen n. gen. (middle Miocene–early middle Pliocene) to include the southeastern Pacific Ocean species D. hupeanus (Philippi, 1887) n. comb. and D. remondi (Philippi, 1887) n. comb., and Ckaraosippur n. gen. (earliest middle Miocene–Pliocene) for C. calderensis (Möricke, 1896) n. comb. (Chile) and C. camachoi n. sp. (Argentina). Both genera are the youngest survivors of the tribe Chlamydini in southern South America. None of them are related to the circumpolar genus Psychrochlamys Jonkers, 2003, and the previous proposal of the dispersal through the Antarctic Circumpolar Current for the species included herein in Dietotenhosen is rejected.
Data from: Co-declining mammal-dung beetle faunas throughout the Atlantic Forest biome of South America
The millennial-scale evolutionary relationships between mammals and dung beetles have been eroded due to several drivers of contemporary biodiversity loss. Although some evidence of co-decline has been shown for mammals and dung beetles at some Neotropical sites, a biome-scale analysis for the entire Atlantic Forest of South America would strengthen our understanding of how relictual sets of mammal species can affect dung beetle co-occurrences and co-declines. We therefore collated hundreds of assemblages of both dung beetles and medium- to large-bodied mammals throughout the world's longest tropical forest latitudinal gradient to examine to what extent mammal assemblages may exert a positive influence on dung beetle species composition and functional assembly, and whether this relationship is scale dependent. We also collated several climatic and other environmental variables to examine the degree to which they shape mammal-dung beetle relationships. The relationships between local mammal and dung beetle faunas were examined using regression models, variation partitioning, dissimilarity indices, and ecological networks. We found a clear positive relationship between mammal and dung beetle species richness across this forest biome, indicating an ongoing process of mammal-dung beetle niche-mediated co-decline. We found a strong relationship between the species composition of both taxa, in which dung beetle species dissimilarity apparently track changes in mammalian dissimilarity, typically in 80% of all cases. Co-variables such as phytomass and climatic variables also influenced mammal-dung beetle patterns of co-decline along the Atlantic Forest. We conclude that dung beetle diversity and community assembly are shaped by the remaining co-occurring mammal assemblages and their functional traits, and both groups were governed by environmental features. We emphasize that ecosystem-wide effects of mammal population declines remain poorly understood both quantitatively and qualitatively, and curbing large vertebrate defaunation will ensure the persistence of co-dependent species.
Data from: Comparison of population genetic patterns in two widespread freshwater mussels with contrasting life histories in western North America
We investigate population genetic structuring in Margaritifera falcata, a freshwater mussel native to western North America, across the majority of its geographical range. We find shallow rangewide genetic structure, strong population-level structuring and very low population diversity in this species, using both mitochondrial sequence and nuclear microsatellite data. We contrast these patterns with previous findings in another freshwater mussel species group (Anodonta californiensis/A. nuttalliana) occupying the same continental region and many of the same watersheds. We conclude that differences are likely caused by contrasting life history attributes between genera, particularly host fish requirements and hermaphroditism. Further, we demonstrate the occurrence of a 'hotspot' for genetic diversity in both groups of mussels, occurring in the vicinity of the lower Columbia River drainage. We suggest that stream hierarchy may be responsible for this pattern and may produce similar patterns in other widespread freshwater species.
Data from: Evolution of Manduca sexta hornworms and relatives: biogeographical analysis reveals an ancestral diversification in Central America
The hawkmoth genus Manduca is a diverse group of very large, conspicuous moths that has served as an important model across many biological disciplines. Two species in particular, the tobacco hornworm (Manduca sexta) and the tomato hornworm (Manduca quinquemaculatus) have been researched extensively. Studies across biological fields have referred to these two species as being closely related or even sister species, but the extent to which these two model organisms are related remains largely unknown. We conducted a comprehensive multi-gene phylogenetic analysis of Manduca, based on both an ML and Bayesian framework, which resulted in a monophyletic Manduca but only when two other genera, Dolba and Euryglottis are included. We tentatively conclude that the sister group to Manduca sexta comprises the Caribbean M. afflicta and M. johanni, and the sister lineage to this clade includes M. quinquemaculatus and the Hawaiian M. blackburni. Thus, M. sexta and M. quinquemaculatus are closely related, but are not sister species. Biogeographical analyses reveal an ancestral center of diversification in Central America, and Manduca appears to have subsequently colonized North and South America. Our phylogeny provides an important foundation for comparative studies of two model organisms and their relatives.
Data from: Rapid evolution of distinct Helicobacter pylori subpopulations in the Americas
For the last 500 years, the Americas have been a melting pot both for genetically diverse humans and for the pathogenic and commensal organisms associated with them. One such organism is the stomach-dwelling bacterium Helicobacter pylori, which is highly prevalent in Latin America where it is a major current public health challenge because of its strong association with gastric cancer. By analyzing the genome sequence of H. pylori isolated in North, Central and South America, we found evidence for admixture between H. pylori of European and African origin throughout the Americas, without substantial input from pre-Columbian (hspAmerind) bacteria. In the US, strains of African and European origin have remained genetically distinct, while in Colombia and Nicaragua, bottlenecks and rampant genetic exchange amongst isolates have led to the formation of national gene pools. We found three outer membrane proteins with atypical levels of Asian ancestry in American strains, as well as alleles that were nearly fixed specifically in South American isolates, suggesting a role for the ethnic makeup of hosts in the colonization of incoming strains. Our results show that new H. pylori subpopulations can rapidly arise, spread and adapt during times of demographic flux, and suggest that differences in transmission ecology between high and low prevalence areas may substantially affect the composition of bacterial populations.
Data from: New Cretaceous lungfishes (Dipnoi, Ceratodontidae) from western North America
Ceratodontid lungfishes are generally rare, poorly represented elements of North America's Mesozoic ecosystems, with previously known maximum diversity in the Late Jurassic. Herein we describe four new species of the form genus Ceratodus, from the Cretaceous of the Western Interior, considerably expanding fossil representation of post-Triassic dipnoans in North America. To model taxonomic and morphologic diversity, we adopt a four-fold system of phenetically based species groups, named for exemplars from the Morrison Formation. Ceratodus kirklandi n. sp. (Potamoceratodus guentheri group) and C. kempae n. sp. (C. frazieri group) represent a hitherto unsampled time interval, the Valanginian. Ceratodus nirumbee n. sp. and C. molossus n. sp. extend the temporal ranges of the C. fossanovum and C. robustus groups upward to the Albian and Cenomanian, respectively. These new occurrences show that ceratodontids maintained their highest diversity from the Late Jurassic through the mid-Cretaceous (Albian–Cenomanian), an interval of ~60 Myr. The existing record suggests that some of the later (mid-Cretaceous) ceratodontids may have been tolerant of salt water; to date, there is no evidence that they aestivated. Only a few occurrences are known from horizons younger than Cenomanian. Demise of ceratodontids appears to be part of a broader pattern of turnover that occurred at the Cenomanian-Turonian boundary in North America.
Data from: New taxa and a case of ephemeral spore production in Lecideaceae from western North America
Cyclohymenia epilithica is a newly described genus and species from Oregon and Washington, U.S.A. It occurs on noncalcareous rock in the oceanic forests west of the crest of the Cascade Range. Unlike most other North American species in the Lecideaceae, it is restricted to shady habitats in cool, wet, temperate climates. It is distinguished from other members of the family by its thick, pale gray green, epilithic thallus; immersed apothecia that superficially appear like perithecia or pycnidia; and ascocarps that usually contain a central sterile column surrounded by a ring-shaped hymenium. The structure and position of the ascocarp appear to be unique among Lecideaceae and related families. The species is also unusual in producing short-lived asci; most collections have barren apothecia. Lecidea atrobrunnea subsp. deplanaica is raised to the species level. The taxon deserves specific rank, not just from its distinctive chemistry, but also from morphology, distribution, and ecology that differ from L. atrobrunnea s.str. The newly described Lecidea uniformis from Oregon and Washington, mainly west of the Cascade crest, is similar in many ways to L. fuscoatra, but the areoles are uniformly brown and do not have a differentiated gray, blackish, or whitish edge. DNA sequence data support the taxa Cyclohymenia epilithica and L. uniformis.
Data from: Northeastern North America as a potential refugium for boreal forests in a warming climate
High precipitation in boreal northeastern North America could help forests withstand the expected temperature-driven increase in evaporative demand, but definitive evidence is lacking. Using a network of tree-ring collections from 16,450 stands across 583,000 km2 of boreal forests in Québec, Canada, we observe a latitudinal shift in the correlation of black spruce growth with temperature and reduced precipitation, from negative south of 49°N to largely positive to the north of that latitude. Our results suggest that the positive effect of a warmer climate on growth rates and growing season length north of 49°N outweighs the potential negative effect of lower water availability. Unlike the central and western portions of the continent's boreal forest, northeastern North America may act as a climatic refugium in a warmer climate.
Data from: Colour lightness of dragonfly assemblages across North America and Europe
Dark-coloured ectotherms absorb energy from the environment at higher rates than light-coloured ectotherms. The thermal melanism hypothesis (TMH) states that this physical mechanism links the colour lightness of the body surfaces of ectotherms to their thermal environment and hence to their geographical distribution. Studies on different insect taxa in Europe found support for this prediction of the TMH. However, whether these results hold also for other biogeographical regions remains unclear. Here, we quantify and map the colour lightness of dragonfly species in North America and directly compare our results to previously published findings for Europe. We estimated the colour lightness of 152 North American dragonfly species from published illustrations, compiled their distribution data from the literature and combined all these data with six biologically relevant environmental variables. We evaluated the importance of phylogenetic autocorrelation for the spatial variation of mean colour lightness of dragonfly assemblages (grid cells of approximately 50 km × 50 km size) by repeating all analyses also for the phylogenetically predicted component of the colour lightness of species and the species-specific deviation from this prediction. We also accounted for spatial autocorrelation with autoregressive error models. All statistical approaches showed that dragonfly assemblages from both continents consistently tended to be darker coloured in regions with cold climates and lighter coloured in regions with warm climates. Regression slopes, however, were significantly less steep, and the amount of variance explained by environmental variables was lower for North America than for Europe. Our results highlight the importance of colour lightness for the distribution of dragonfly species, but they also indicate that idiosyncrasies of the continents modify the general pattern.
Data from: Phylogeography and species delimitation in convict cichlids (Cichlidae: Amatitlania): implications for taxonomy and Plio–Pleistocene evolutionary history in Central America
We investigate phylogeographic patterns and delimit species boundaries within Amatitlania, a genus of Central American cichlid fishes. Phylogenetic analyses of mitochondrial DNA sequences from 318 individuals spanning the geographical ranges of all three currently recognized Amatitlania species strongly supported one major clade, with a relatively diverged subclade corresponding to A. kanna samples from eastern Costa Rica and Panama. Gene trees and networks revealed marked incongruences between phylogeographic structure and morpho-species taxonomy as a result of species-level polyphyly. Bayes factor comparisons of species delimitation models accounting for incomplete lineage sorting under the multispecies coalescent decisively supported the recognition of two distinct species within Amatitlania corresponding to Amatitlania nigrofasciata and A. kanna lineages. The only clearly genetically and morphologically diagnosable species was A. kanna. These results strongly suggest that incomplete lineage sorting provides the best explanation for the polyphyly of A. kanna, whereas the polyphyly of A. siquia is likely a result of an imperfect taxonomy. Additional insights from coalescent-dating, network, and historical demographic analyses suggested that the two species of Amatitlania diversified only since the early Pleistocene, and that A. nigrofasciata experienced population expansions from approximately 200 000 years ago in the mid-late Pleistocene onward. We discuss implications of our results for the taxonomy and evolutionary history of Amatitlania and, more broadly, of Central American freshwater fishes.
Data from: Lincoln estimates of mallard (Anas platyrhynchos) abundance in North America
Estimates of range-wide abundance, harvest, and harvest rate are fundamental for sound inferences about the role of exploitation in the dynamics of free-ranging wildlife populations, but reliability of existing survey methods for abundance estimation is rarely assessed using alternative approaches. North American mallard populations have been surveyed each spring since 1955 using internationally coordinated aerial surveys, but population size can also be estimated with Lincoln's method using banding and harvest data. We estimated late summer population size of adult and juvenile male and female mallards in western, midcontinent, and eastern North America using Lincoln's method of dividing (i) total estimated harvest, H, by estimated harvest rate, h, calculated as (ii) direct band recovery rate, f, divided by the (iii) band reporting rate, p. Our goal was to compare estimates based on Lincoln's method with traditional estimates based on aerial surveys. Lincoln estimates of adult males and females alive in the period June–September were 4.0 (range: 2.5–5.9), 1.8 (range: 0.6–3.0), and 1.8 (range: 1.3–2.7) times larger than respective aerial survey estimates for the western, midcontinent, and eastern mallard populations, and the two population estimates were only modestly correlated with each other (western: r = 0.70, 1993–2011; midcontinent: r = 0.54, 1961–2011; eastern: r = 0.50, 1993–2011). Higher Lincoln estimates are predictable given that the geographic scope of inference from Lincoln estimates is the entire population range, whereas sampling frames for aerial surveys are incomplete. Although each estimation method has a number of important potential biases, our review suggests that underestimation of total population size by aerial surveys is the most likely explanation. In addition to providing measures of total abundance, Lincoln's method provides estimates of fecundity and population sex ratio and could be used in integrated population models to provide greater insights about population dynamics and management of North American mallards and most other harvested species.
Data from: Herteliana schuyleriana (Squamarinaceae), a new crustose lichen widespread in the Appalachian Mountains of eastern North America
Herteliana schuyleriana is described as new to science based on collections from throughout the Appalachian Mountains of eastern North America. Taxonomic placement is inferred from molecular phylogenic analysis of mtSSU sequence data that recovered the taxon as sister to the type species of Herteliana, H. gagei, and strongly supported these taxa as embedded within the Squamarinaceae. The new species is characterized by its occurrence on non-calcareous shaded rocks in inland forested habitats (vs. exposed maritime oceanic habitats), its greenish-blue crustose thallus, presence of abundant blastidia on the thallus surface, frequent sterility, and by the production of roccellic/angardianic acid together with occasional trace amounts of psoromic acid as accessories to atranorin.
Data from: A review of the lichens of the Dare Regional Biodiversity Hotspot in the Mid-Atlantic Coastal Plain of North Carolina, eastern North America
The results of a large-scale biodiversity inventory of lichens (including lichenicolous and allied fungi) in the Dare Regional Biodiversity Hotspot (DRBH) are presented. The DRBH is a region within the Mid-Atlantic Coastal Plain (MACP) of eastern North America that was recently delineated based on its unique and diverse lichen communities relative to other areas of the Atlantic Coast. Drawing on 4,952 newly generated voucher specimens from 49 sites, patterns of biodiversity and biogeography are presented and discussed within the context of both the DRBH and the broader MACP. Relationships between natural communities, vegetation, and lichen communities are discussed, as are threats to the lichen biota. A series of conservation actions are presented together with avenues for future study. In addition, supplementary resources are provided in the form of: (a) a checklist of DRBH lichens, lichenicolous fungi, and allied fungi; (b) keys to DRBH lichens and lichenicolous and allied fungi; and (c) formal descriptions of the following species new to science that were discovered during the inventory: Albemarlea pamlicoensis gen. et. sp. nov., Arthonia agelastica sp. nov. (on Lecanora louisianae B. de Lesd.), Arthonia hodgesii sp. nov. (on Graphis lineola), Arthonia stevensoniana sp. nov. (on Haematomma accolens), Lichenochora haematommatum sp. nov. (on Haematomma persoonii), Megalaria alligatorensis sp. nov., Minutoexcipula miniatoexcipula sp. nov. (on Pertusaria epixantha), Trichosphaerella buckii sp. nov. (on Punctelia rudecta).
Data from: Impact of population expansion on genetic diversity and structure of river otters (Lontra canadensis) in central North America
Populations of North American river otters (Lontra canadensis) declined throughout large portions of the continent during the early 1900s due to habitat degradation and unregulated trapping. River otters had been extirpated in North Dakota (ND), but the Red River Valley has since been recolonized, with potential source populations including the neighboring states of Minnesota or South Dakota, or the Canadian province of Manitoba (MB). We genotyped 9 microsatellite loci in 121 samples to determine the source population of river otters in the Red River Valley of ND, as well as to assess population structure and diversity of river otters in central North America. Overall, genetic diversity was high, with an average observed heterozygosity of 0.58. Genetic differentiation was low (F ST < 0.05) between river otters in ND and those of Minnesota, suggesting that eastern ND was recolonized by river otters from Minnesota. River otters from MB were genetically distinct from all other sampled populations. Low genetic differentiation (F ST = 0.044) between South Dakota and Louisiana (LA) suggested that reintroductions using LA stock were successful. The genetic distinctiveness of river otters from different geographic regions should be considered when deciding on source populations for future translocations.
Data from: Phylogeny of genus Cupuladria (Bryozoa: Cheilostomata) in the Neogene of tropical America
We used 57 morphometric characters to discriminate 17 extant and fossil Cupuladria species and analyzed their phylogenetic relationships in relation to extant Discoporella species. Data were gathered from 496 extant and fossil Cupuladria specimens ranging in age from early Miocene to Recent and distributed from the Caribbean to tropical eastern Pacific. A first series of discriminant analyses distinguished three morphological groups: Cupuladria with vicarious avicularia, Cupuladria without vicarious avicularia, and Discoporella. Further discriminant analyses identified 17 species of Cupuladria. Cladistic analyses of these three groups yielded four equally parsimonious trees. All of the consensus trees exhibited the same topology, dividing the 25 tropical American cupuladriids into four distinct monophyletic clades, including Discoporella, and are consistent with previous molecular phylogenies except that there are no molecular data for the CV2 clade. Diversification of species was higher in the CV1 and CV2 clades than CNV clade, and involved mostly Caribbean species. Cupuladria with vicarious clade 1 (CV1) includes: C. monotrema, C. pacificiensis, C. exfragminis, C. cheethami, C. biporosa, and four new species: C. pervagata, C. floridensis, C. colonensis and C. dominicana. Cupuladria with vicarious clade 2 (CV2) includes: C. multesima, C. incognita, and three new species C. collyrida, C. veracruxiensis and C. planissima. Cupuladria clade without vicarious (CNV) includes: C. surinamensis, C. panamensis, and one new species C. gigas. The stratigraphic occurrence of species is consistent with cladogram topology within clades. However hypothesized cladistic relations among clades are the reverse of their stratigraphic occurrence with younger clade CNV appearing as the hypothetical ancestor of the two older clades CV1 and CV2. More extensive collections of early to middle Miocene specimens of Cupuladria and Discoporella will be required to resolve this apparent paradox.
Data from: Fish faunal provinces of the conterminous United States of America reflect historical geography and familial composition
Although the conterminous USA has a long history of ichthyological exploration, the description of biogeographical provinces has been ad hoc. In this study we quantitatively determined fish faunal provinces and interpreted them in the context of the geological history of North America. We also evaluated influences of major river basin occupancy and contemporary environmental factors on provincial patterns. Our data set comprised 794 native fishes, which we used to generate a presence and absence matrix for U.S. Geological Survey (USGS) four-digit hydrologic units. Three nested data sets were analysed separately: primary freshwater families, continental freshwater families (including primary and secondary families) and all freshwater families (including primary, secondary and peripheral families). We used clustering analysis to delimit faunal breaks and one-way analysis of similarity (ANOSIM) to determine significance among clusters (i.e. provinces). We used an indicator-species analysis to identify species that contributed most to province delineations and a similarity-percentage (SIMPER) analysis to describe the relative influence of representatives from each category (i.e. primary, secondary, peripheral) on provincial boundaries. Lastly, we used a parsimony redundancy analysis to determine the roles of historical (i.e. major river basin) and contemporary environmental factors in shaping provinces. Analysis of the nested data sets revealed lessening provincial structure with inclusion of more families. There were 10 primary freshwater provinces, 9 continental freshwater provinces and 7 all freshwater provinces. Major basin occupancy, but not contemporary environmental factors, explained substantial variance in faunal similarities among provinces. However, provincial boundaries did not conform strictly to modern river basins, but reflected river-drainage connections of the Quaternary. Provinces represent broad-scale patterns of endemism and provide a starting point for future studies. Relative malleability of province boundaries in the continental interior highlights this region as biogeographically diverse and dynamic. Interior-core provinces of this region (Central Gulf Coastal Plains, Northern Interior) have not been recognized previously and warrant further study.
Data from: Genome-wide evidence of environmentally mediated secondary contact of European green crab (Carcinus maenas) lineages in eastern North America
Genetic-environment associations are increasingly revealed through population genomic data and can occur through a number of processes, including secondary contact, divergent natural selection, or isolation-by-distance. Here we investigate the influence of the environment, including seasonal temperature and salinity, on the population structure of the invasive European green crab (Carcinus maenas) in eastern North America. Green crab populations in eastern North America are associated with two independent invasions, previously shown to consist of distinct northern and southern ecotypes, with a contact zone in southern Nova Scotia, Canada. Using a RAD-seq panel of 9137 genome-wide SNPs, we detected 41 SNPs (0.49%) whose allele frequencies were highly correlated with environmental data. A principal components analysis of 25 environmental variables differentiated populations into northern, southern, and admixed sites in concordance with the observed genomic spatial structure. Furthermore, a spatial principal components analysis conducted on genomic and geographic data revealed a high degree of global structure (p<0.0001) partitioning a northern and southern ecotype. Redundancy and partial redundancy analyses revealed that among the environmental variables tested, winter sea surface temperature had the strongest association with spatial structuring, suggesting that it is an important factor defining range and expansion limits of each ecotype. Understanding environmental thresholds associated with intraspecific diversity will facilitate the ability to manage current and predict future distributions of this aquatic invasive species.
Data from: ddRAD‐seq data reveal significant genome‐wide population structure and divergent genomic regions that distinguish the mallard and close relatives in North America
Recently evolved species typically share genetic variation across their genomes due to incomplete lineage sorting and/or ongoing gene flow. Given only subtle allele frequency differences at most loci and the expectation that divergent selection may affect only a tiny fraction of the genome, distinguishing closely related species based on multi‐locus data requires substantial genomic coverage. In this study, we used ddRAD‐seq to sample the genomes of five recently diverged, New World "mallards" (Anas spp.), a group of dabbling duck species characterized by diagnosable phenotypic differences but minimal genetic differentiation. With increased genomic sampling, we aimed to characterize population structure within this group and identify genomic regions that may have experienced divergent selection during speciation. We analyzed 3,017 autosomal ddRAD‐seq loci and 177 loci from the Z‐chromosome. In contrast to previous studies, the ddRAD‐seq data were sufficient to assign individuals to their respective species or subspecies and to generate estimates of gene flow in a phylogenetic framework. We find limited evidence of contemporary gene flow between the dichromatic mallard and several monochromatic taxa, but find evidence for historical gene flow between some monochromatic species pairs. We conclude that the overall genetic similarity of these taxa likely reflects retained ancestral polymorphism rather than recent and extensive gene flow. Thus, despite recurring cases of hybridization in this group, our results challenge the current dogma predicting the genetic extinction of the New World monochromatic dabbling ducks via introgressive hybridization with mallards. Moreover, ddRAD‐seq data were sufficient to identify previously unknown outlier regions across the Z‐chromosome and several autosomal chromosomes, regions that may have been involved in the diversification of species in this recent radiation.
Data from: Environmental extremes drive population structure at the northern range limit of Atlantic salmon in North America
Conservation of exploited species requires an understanding of both genetic diversity and the dominant structuring forces, particularly near range limits, where climatic variation can drive rapid expansions or contractions of geographic range. Here, we examine population structure and landscape associations in Atlantic salmon (Salmo salar) across a heterogeneous landscape near the northern range limit in Labrador, Canada. Analysis of two amplicon-based data sets containing 101 microsatellites and 376 single nucleotide polymorphisms (SNPs) from 35 locations revealed clear differentiation between populations spawning in rivers flowing into a large marine embayment (Lake Melville) compared to coastal populations. The mechanisms influencing the differentiation of embayment populations were investigated using both multivariate and machine-learning landscape genetic approaches. We identified temperature as the strongest correlate with genetic structure, particularly warm temperature extremes and wider annual temperature ranges. The genomic basis of this divergence was further explored using a subset of locations (n=17) and a 220K SNP array. SNPs associated with spatial structuring and temperature mapped to a diverse set of genes and molecular pathways, including regulation of gene expression, immune response, and cell development and differentiation. The results spanning molecular marker types and both novel and established methods clearly show climate-associated, fine-scale population structure across an environmental gradient in Atlantic salmon near its range limit in North America, highlighting valuable approaches for predicting population responses to climate change and managing species sustainability.
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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.