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531 results for “Genomic differentiation”
Raw differential gene expression data, data S1, from: Molecular cascades and cell type-specific signatures in ASD revealed by single cell genomics
<p>Genomic profiling in post-mortem brain from autistic individuals has consistently revealed convergent molecular changes. What drives these changes and how they relate to genetic susceptibility in this complex condition is not understood. We performed deep single nuclear RNA sequencing (snRNAseq) to examine cell composition and transcriptomics, identifying dysregulation of cell type-specific gene regulatory networks (GRNs) in autism, which we corroborated using snATAC-seq and spatial transcriptomics. Transcriptomic changes were primarily cell type-specific, involving multiple cell types, most prominently interhemispheric and callosal-projecting neurons, interneurons within superficial laminae, and distinct glial reactive states involving oligodendrocytes, microglia, and astrocytes. Autism-associated GRN drivers and their targets were enriched in rare and common genetic risk variants, connecting autism genetic susceptibility and cellular and circuit alterations in the human brain. This data is the raw differential gene expression comparing ASD versus CTL subjects for each cell cluster. </p>
Predictors of genomic differentiation within a hybrid taxon
<p>Hybridization is increasingly recognized as an important evolutionary force. Novel genetic methods now enable us to address how the genomes of parental species are combined in hybrid lineages. However, we still do not know the relative importance of admixed proportions, genome architecture and local selection in shaping hybrid genomes. Here, we take advantage of the genetically divergent island populations of Italian sparrow on Crete, Corsica and Sicily to investigate the predictors of genomic variation within a hybrid taxon. We test if differentiation is affected by recombination rate, selection, or variation in ancestry proportions. We find that the relationship between recombination rate and differentiation is less pronounced within hybrid lineages than between the parent species, as expected if purging of minor parent ancestry in low recombination regions reduces the variation available for differentiation. In addition, we find that differentiation between islands is correlated with differences in signatures of selection in two out of three comparisons. Signatures of selection within islands are correlated across all islands, suggesting that shared selection may mould genomic differentiation. The best predictor of strong differentiation within islands is the degree of differentiation from house sparrow, and hence loci with Spanish sparrow ancestry may vary more freely. Jointly, this suggests that constraints and selection interact in shaping the genomic landscape of differentiation in this hybrid species.</p>
Data from: Local adaptation in shell shape traits of a brooding chiton with strong population genomic differentiation
<p class="MsoNormal"><span>Comparing divergence in quantitative tr</span><span>aits and neutral m</span><span>olecular markers, such as <em>Q</em><sub>ST</sub><em>–F</em><sub>ST</sub> comparisons, provides a means to distinguish between natural selection and genetic drift as causes of population differentiation in complex polygenic traits. </span><em>Onithochiton neglectus</em> (Rochebrune, 1881) is a morphologically variable chiton endemic to New Zealand, with populations distributed over a broad latitudinal environmental gradient. In this species, the morphological variants cluster into two geographically separated shell shape groups, and the phenotypic variation in shell shape has been hypothesised to be adaptive. Here, we assessed this hypothesis by comparing neutral genomic differentiation between populations (<em><span>F<sub>ST</sub></span></em><span>)</span> with an index of phenotypic differentiation (<em>P<sub>ST</sub></em>). We used 7,562 putatively neutral single nucleotide polymorphisms (SNPs) across 15 populations and three clades of <em>O. neglectus</em> throughout New Zealand to infer <em><span>F<sub>ST</sub></span></em>. <em>P<sub>ST</sub></em> was calculated from 18 shell shape traits and gave highly variable estimates across populations, clades and shape groups. By systematically comparing <em>P<sub>ST</sub></em> with <em>F<sub>ST</sub></em><sub>,</sub> we identified evidence of local adaptation in a number of the <em>O. neglectus </em>shell shape traits. This <span>supports the hypothesis that shell shape could be an adaptive trait, potentially correlated with the ability to live and raft in kelp holdfasts.</span></p>
Novel Genomic Regions linked to Ascochyta blight Resistance in two differentially resistant cultivars of chickpea
<p><em>Ascochyta</em> blight (AB) caused by the fungal pathogen <em>Ascochyta rabiei</em> is a devastating foliar disease of chickpea (<em>Cicer arietinum</em> L.). Genotyping-by-sequencing (GBS) has been used in the current study for the identification of AB associated quantitative trait loci (QTLs) and their gene(s). We evaluated genotyping-by-sequencing (GBS)-based approach for mapping QTLs associated with AB resistance in chickpea using two recombinant inbred lines populations (AB<sub>3279</sub> and AB<sub>482</sub>) derived from two crosses ILC 1929 X ILC 3279 and ILC 1929 X ILC 482, under six different environments. In total, twenty-one different genomic regions were identified on linkage groups CalG02 and CalG04 pertaining to AB resistance in both populations AB<sub>3279</sub> and AB<sub>482</sub>. Four genomic regions were detected on CalG02 in the population AB<sub>3279</sub> and nine major genomic regions were associated with AB resistance on CaLG04, five out of them were common to both resistant parents ‘ILC3279’ and ‘ILC482’, and eight minor genomic regions with two out of them common between both populations. These regions contain 1,118 SNPs significantly associated (p ≤ 0.001) with AB resistance. Gene ontology (GO) assigned these QTLs to 319 genes, many of which were associated with stress and disease resistance, with most important genes belonging to resistance gene families including Leucine-Rich Repeat (LRR), and transcription factors families. Our results may refer to the flowering-associated gene GIGANTEA as a possible key factor in AB resistance in chickpea. The results have narrowed the AB resistance associated regions on the chickpea physical map and the associated markers will help in breeding programs for chickpea improvement.</p>
High heterogeneity in genomic differentiation between phenotypically divergent songbirds: A test of mitonuclear co-introgression
<p>Comparisons of genomic variation among closely related species often show more differentiation in mitochondrial DNA (mtDNA) and sex chromosomes than in autosomes, a pattern expected due to the differing effective population sizes and evolutionary dynamics of these genomic components. Yet, introgression can cause species pairs to deviate dramatically from general differentiation trends. The yellowhammer (<em>Emberiza</em> <em>citrinella</em>) and pine bunting (<em>E</em>. <em>leucocephalos</em>) are hybridizing avian sister species that differ greatly in appearance and moderately in nuclear DNA, but that show no mtDNA differentiation. This discordance is best explained by adaptive mtDNA introgression—a process that can select for co-introgression at nuclear genes with mitochondrial functions (mitonuclear genes). To better understand these discordant differentiation patterns and characterize nuclear differentiation in this system, we investigated genome-wide differentiation between allopatric yellowhammers and pine buntings and compared it to what was seen previously in mtDNA. We found significant nuclear differentiation that was highly heterogeneous across the genome, with a particularly wide differentiation peak on the sex chromosome Z. We further investigated mitonuclear gene co-introgression between yellowhammers and pine buntings and found support for this process in the direction of pine buntings into yellowhammers. Genomic signals indicative of co-introgression were common in mitonuclear genes coding for subunits of the mitoribosome and electron transport chain complexes. Such introgression of mitochondrial DNA and mitonuclear genes provides a possible explanation for the patterns of high genomic heterogeneity in genomic differentiation seen among some species groups.</p>
Data from: Population genomics reveals multiple drivers of population differentiation in a sex-role-reversed pipefish
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Raw differential gene expression data, data S1, from: Molecular cascades and cell type-specific signatures in ASD revealed by single cell genomics
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A comparison of genomic islands of differentiation across three young avian species pairs
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Data from: Genomic divergence in allopatric Northern Cardinals of the North American warm deserts is linked to behavioral differentiation
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High heterogeneity in genomic differentiation between phenotypically divergent songbirds: A test of mitonuclear co-introgression
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Predictors of genomic differentiation within a hybrid taxon
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Data from: Local adaptation in shell shape traits of a brooding chiton with strong population genomic differentiation
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Genome-wide differentiation by geography not species in taxonomically complex eyebrights (Euphrasia)
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Data from: Divergent and linked selection shape patterns of genomic differentiation between European and North American Atlantic salmon (Salmo salar)
<p>As populations diverge many processes can shape genomic patterns of differentiation. Regions of high differentiation can arise due to divergent selection acting on selected loci, genetic hitchhiking of nearby loci, or through repeated selection against deleterious alleles (linked background selection); this divergence may then be further elevated in regions of reduced recombination. Atlantic salmon (Salmo salar) from Europe and North America diverged >600,000 years ago and despite some evidence of secondary contact, the majority of genetic data indicate substantial divergence between lineages. This deep divergence with potential gene flow provides an opportunity to investigate the role of different mechanisms that shape the genomic landscape during early speciation. Here, using 184,295 SNPs and 80 populations, we investigate the genomic landscape of differentiation across the Atlantic Ocean with a focus on highly differentiated regions and processes shaping them. We found evidence of high (mean FST=0.26) and heterogeneous genomic differentiation between continents. Genomic regions associated with high trans-Atlantic differentiation ranged in size from single loci (SNPs) within important genes to large regions (1-3Mbp) on four chromosomes (Ssa06, Ssa13, Ssa16, and Ssa19). These regions showed signatures consistent with selection, including high linkage disequilibrium despite no local reduction in recombination. Genes and functional enrichment of processes associated with differentiated regions may highlight continental differences in ocean navigation and parasite resistance. Our results provide insight into potential mechanisms underlying differences between continents, and evidence of near fixed and potentially adaptive trans-Atlantic differences concurrent with a background of high genome-wide differentiation supports subspecies designation in Atlantic salmon.</p>
Data from: Population genomic evidence reveals subtle patterns of differentiation in the trophically polymorphic Cuatro Ciénegas cichlid, Herichthys minckleyi
In recent decades, an increased understanding of molecular ecology has led to a reinterpretation of the role of gene flow during the evolution of reproductive isolation and biological novelty. For example, even in the face of ongoing gene flow strong selection may maintain divergent polymorphisms, or gene flow may introduce novel biological diversity via hybridization and introgression from a divergent species. Herein, we elucidate the evolutionary history and genomic basis of a trophically polymorphic trait in a species of cichlid fish, Herichthys minckleyi. We explored genetic variation at three hierarchical levels; between H. minckleyi (n=69) and a closely related species H. cyanoguttatus (n=10), between
Data from: Genome-wide diversity and habitat underlie fine-scale phenotypic differentiation in the rainbow darter (Etheostoma caeruleum)
<p>Adaptation to environmental change requires that populations harbor the necessary genetic variation to respond to selection. However, dispersal-limited species with fragmented populations and reduced genetic diversity may lack this variation and are at an increased risk of local extinction. In freshwater fish species, environmental change in the form of increased stream temperatures places many cold-water species at-risk. We present a study of rainbow darters (<i>Etheostoma caeruleum</i>) in which we evaluated the importance of genetic variation on adaptive potential and determined responses to extreme thermal stress. We compared fine-scale patterns of morphological and thermal tolerance differentiation across eight sites, including a unique lake habitat. We also inferred contemporary population structure using genomic data and characterized the relationship between individual genetic diversity and stress tolerance. We found site-specific variation in thermal tolerance that generally matched local conditions and morphological differences associated with lake-stream divergence. We detected patterns of population structure on a highly local spatial scale that could not be explained by isolation by distance or stream connectivity. Finally, we showed that individual thermal tolerance was positively correlated with genetic variation, suggesting that sites with increased genetic diversity may be better at tolerating novel stress. Our results highlight the importance of considering intraspecific variation in understanding population vulnerability and stress response.</p>
Genomic differentiation and local adaptation on a microgeographic scale in a resident songbird
<p>Elucidating forces capable of driving species diversification in the face of gene flow remains a key goal in evolutionary biology. Song sparrows, Melospiza melodia, occur as 25 subspecies in diverse habitats across North America, are among the continent's most widespread vertebrate species, and are exemplary of many highly variable species for which the conservation of locally adapted populations may be critical to their range-wide persistence. We focus here on six morphologically distinct subspecies resident in the San Francisco Bay region, including three salt-marsh endemics and three residents in upland and riparian habitats adjacent to the Bay. We used reduced-representation sequencing to generate 2,773 SNPs to explore genetic differentiation, spatial population structure, and demographic history. Clustering separated individuals from each of the six subspecies, indicating subtle differentiation at microgeographic scales. Evidence of limited gene flow and low nucleotide diversity across all six subspecies further supports a hypothesis of isolation among locally adapted populations. We suggest that natural selection for genotypes adapted to salt marsh environments and changes in demography over the past century have acted in concert to drive the patterns of diversification reported here. Our results offer evidence of microgeographic specialization in a highly polytypic bird species long discussed as a model of sympatric speciation and rapid adaptation, and they support the hypothesis that conserving locally adapted populations may be critical to the range-wide persistence of similarly highly variable species.</p>
Data from: Genomic islands of differentiation in two songbird species reveal candidate genes for hybrid female sterility
Hybrid sterility is a common first step in the evolution of postzygotic reproductive isolation. According to Haldane's Rule it affects predominantly the heterogametic sex. While the genetic basis of hybrid male sterility in organisms with heterogametic males has been studied for decades, the genetic basis of hybrid female sterility in organisms with heterogametic females has received much less attention. We investigated the genetic basis of reproductive isolation in two closely related avian species, the Common Nightingale (Luscinia megarhynchos) and the Thrush Nightingale (L. luscinia), that hybridize in a secondary contact zone and produce viable hybrid progeny. In accordance with Haldane's Rule, hybrid females are sterile, while hybrid males are fertile, allowing gene flow to occur between the species. Using transcriptomic data from multiple individuals of both nightingale species we identified genomic islands of high differentiation (FST) and of high divergence (Dxy), and we analyzed gene content and patterns of molecular evolution within these islands. Interestingly, we found that these islands were enriched for genes related to female meiosis and metabolism. The islands of high differentiation and divergence were also characterized by higher levels of linkage disequilibrium than the rest of the genome in both species indicating that they might be situated in genomic regions of low recombination. This study provides one of the first insights into genetic basis of hybrid female sterility in organisms with heterogametic females.
Data from: Gene duplication, population genomics and species-level differentiation within a tropical mountain shrub
Gene duplication leads to paralogy, which complicates the de novo assembly of genotyping-by-sequencing (GBS) data. The issue of paralogous genes is exacerbated in plants, because they are particularly prone to gene duplication events. Paralogs are normally filtered from GBS data before undertaking population genomics or phylogenetic analyses. However, gene duplication plays an important role in the functional diversification of genes and it can also lead to the formation of postzygotic barriers. Using populations and closely related species of a tropical mountain shrub, we examine: (1) the genomic differentiation produced by putative orthologs, and (2) the distribution of recent gene duplication among lineages and geography. We find high differentiation among populations from isolated mountain peaks and species-level differentiation within what is morphologically described as a single species. The inferred distribution of paralogs among populations is congruent with taxonomy and shows that GBS could be used to examine recent gene duplication as a source of genomic differentiation of non-model species.
Data from: Landscape genomics and a common garden trial reveal adaptive differentiation to temperature across Europe in the tree species Alnus glutinosa
The adaptive potential of tree species to cope with climate change has important ecological and economic implications. Many temperate tree species experience a wide range of environmental conditions, suggesting high adaptability to new environmental conditions. We investigated adaptation to regional climate in the drought-sensitive tree species Alnus glutinosa (Black alder), using a complementary approach that integrates genomic, phenotypic and landscape data. A total of 24 European populations were studied in a common garden and through landscape genomic approaches. Genotyping-By-Sequencing was used to identify SNPs across the genome, resulting in 1990 SNPs. Although a relatively low percentage of putative adaptive SNPs was detected (2.86% outlier SNPs), we observed clear associations among outlier allele frequencies, temperature, and plant traits. In line with the typical drought avoiding nature of A. glutinosa, leaf size varied according to a temperature gradient and significant associations with multiple outlier loci were observed, corroborating the ecological relevance of the observed outlier SNPs. Moreover, the lack of isolation-by-distance, the very low genetic differentiation among populations and the high intra-population genetic variation all support the notion that high gene exchange combined with strong environmental selection promotes adaptation to environmental cues.
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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)
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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.