Human genome-wide variations in the Massim region
Ontology highlight
ABSTRACT:
PROVIDER: EGAS00001006010 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:Linguistic and cultural evidence suggests that Madagascar was the final point of two major dispersals of Austronesian and Bantu speaking populations. Today, Mikea are described as the last known Malagasy population reported to be still practising a hunter-gatherer life-style. It is unclear, however, whether Mikea descend from a remnant population that existed before the arrival of Austronesian and Bantu agriculturalists or whether it is only their life-style that separates them from the other contemporary populations of South Madagascar. In order to address these questions we have performed a genome wide analysis of >700,000 SNP markers on 21 Mikea, 24 Vezo and 24 Temoro individuals together with 50 individuals from Bajo and Lebbo populations from Indonesia. Our analyses of these data in the context of data available from other Southeast Asian and African populations reveal that all three Malagasy populations are derived from the same admixture event involving Austronesian and Bantu sources. In contrast to the fact that most of the vocabulary of the Malagasy speakers is derived from the Barito group of the Austronesian language family we observe that only one third of their genetic ancestry is related to the populations of Java-Kalimantan-Sulawesi area. Because no additional ancestry components distinctive to for the Mikea were found, it is likely that they have adopted their hunter-gatherer way of life by through cultural reversion. 69 samples were analysed with the Illumina platform OmniExpress BeadChips and are described herein.
2013-12-19 | E-GEOD-53445 | biostudies-arrayexpress
Project description:Linguistic and cultural evidence suggests that Madagascar was the final point of two major dispersals of Austronesian and Bantu speaking populations. Today, Mikea are described as the last known Malagasy population reported to be still practising a hunter-gatherer life-style. It is unclear, however, whether Mikea descend from a remnant population that existed before the arrival of Austronesian and Bantu agriculturalists or whether it is only their life-style that separates them from the other contemporary populations of South Madagascar. In order to address these questions we have performed a genome wide analysis of >700,000 SNP markers on 21 Mikea, 24 Vezo and 24 Temoro individuals together with 50 individuals from Bajo and Lebbo populations from Indonesia. Our analyses of these data in the context of data available from other Southeast Asian and African populations reveal that all three Malagasy populations are derived from the same admixture event involving Austronesian and Bantu sources. In contrast to the fact that most of the vocabulary of the Malagasy speakers is derived from the Barito group of the Austronesian language family we observe that only one third of their genetic ancestry is related to the populations of Java-Kalimantan-Sulawesi area. Because no additional ancestry components distinctive to for the Mikea were found, it is likely that they have adopted their hunter-gatherer way of life by through cultural reversion.
2013-12-19 | GSE53445 | GEO
Project description:Illumina single nucleotide polymorphism (SNP) array data were generated to study genome-wide patterns of genomic variation on Sumba and Timor, two small islands in eastern Indonesia. Both islands have a complex history from their initial settlement ~50,000 years ago, to admixture with Austronesian-speaking groups during the Neolithic farming expansion, and more recent intra-island gene flow and community interactions. As part of this detailed microgeographic study, we also collected associated cultural and linguistic information. The primary study location was Sumba, for which we genotyped SNPs in 235 individuals from eight communities that span the island, including groups that speak most of Sumba’s nine languages. Particular attention was paid to genomic data that are informative for recent aspects of population history, including reconstructions of past gene flow, socio-genetic interactions and possible signals of selection.
2016-07-14 | GSE76645 | GEO
Project description:The Human Retina Cell Atlas (HRCA) integrates data from a wide range of ancestry backgrounds, making it a highly valuable resource for understanding retinal cell types and their molecular profiles. By collecting data from 60 donors with diverse ancestry backgrounds, the atlas enabled the investigation of how ancestry affects gene expression patterns and chromatin accessibility across retinal cell types. The project's findings on gene expression and chromatin openness provide critical insights into how genetic heritage influences retinal function and susceptibility to certain eye conditions. The ancestry-related data can also help identify population-specific variations in retinal biology, potentially paving the way for more personalized diagnosis and treatment of eye disorders across different ethnic groups.
2025-10-14 | GSE281526 | GEO
Project description:Free-breeding dogs have occupied the Galápagos islands at least since the 1830s, however, it was not until the 1900s that dog populations grew substantially, endangering wildlife and spreading disease. In 1981, authorities sanctioned the culling of free-roaming dogs. Yet there are currently large free-roaming dog populations of unknown ancestry on the islands of Isabela and Santa Cruz, whose ancestry has never been assessed on a genome-wide scale. Thus, we performed a complete genomic analysis of the current Galápagos dog population as well as historical Galápagos dogs sampled between 1969 and 2003, testing for population structure, admixture, and shared ancestry. Our dataset included samples from 187 modern and six historical Galápagos dogs, together with whole genome sequence from over 2,000 modern purebred and village dogs. Our results indicate that modern Galápagos dogs are recently admixed with purebred dogs but show no evidence of a population bottleneck related to the culling. Additionally, IBD analyses reveal evidence of shared shepherd-dog ancestry in the historical Galápagos dogs. Overall, our results demonstrate that the 1980s culling of dogs was ineffective in controlling population size and did little to reduce genetic diversity, instead producing a stable and expanding population with genomic signatures of historical dogs remaining today. The insights from this study can be used to improve population control strategies for the Galápagos Islands and other endangered endemic communities worldwide.
2024-10-01 | GSE276576 | GEO
Project description:Only a few scattered groups with oral traditions of Khoe-San hunter-gatherer ancestry remain in southeastern Africa. We investigate genomic variation of remaining individuals from two South African groups with oral histories connecting them to eastern San groups, i.e., the San from Lake Chrissie and the Duma San of the uKhahlamba-Drakensberg. Using ~2.2 million genetic markers, combined with comparative published datasets, we show that the Lake Chrissie San have genetic ancestry from both Khoe-San (likely the ||Xegwi San) and Bantu-speakers. Specifically, we found that the Lake Chrissie San are closely related to current southern San groups (i.e. the Karretjie People). Duma San individuals, on the other hand, were genetically similar to southeastern Bantu speakers from South Africa. Samples were genotyped on the Illumina Omni2.5M (HumanOmni25-8v1-2_A1) SNP chip. Results were analyzed using the software GenomeStudio 2011.1 and the data were exported to Plink format, aligned to Human Genome build version 37.
2016-09-21 | E-MTAB-5119 | biostudies-arrayexpress
Project description:Individuals from different populations vary considerably in their susceptibility to immune-related diseases. To understand how genetic variation and natural selection contribute to these differences, we tested for the effects of African versus European ancestry on the transcriptional response of primary macrophages to live bacterial pathogens. 12% of macrophage-expressed genes show ancestry-associated differences in the gene regulatory response to infection, and African ancestry specifically predicts a stronger inflammatory response and reduced intracellular bacterial growth. A large proportion of these differences are under genetic control: for 569 genes, more than 75% of ancestry effects on the immune response can be explained by a single cis- or trans-acting eQTL. Finally, we show that genetic effects on the immune response are strongly enriched for recent, population-specific signatures of adaptation. Together, our results demonstrate how historical selective events continue to shape human phenotypic diversity today, including for traits that are central to coping with infection. Transcriptomic profiles of 503 infected (Listeria and Salmonella) and non-infected samples at 2hr time point.
2016-09-06 | E-GEOD-81046 | biostudies-arrayexpress
Project description:Individuals from different populations vary considerably in their susceptibility to immune-related diseases. To understand how genetic variation and natural selection contribute to these differences, we tested for the effects of African versus European ancestry on the transcriptional response of primary macrophages to live bacterial pathogens. A total of 9.3% of macrophage-expressed genes show ancestry-associated differences in the gene regulatory response to infection, and African ancestry specifically predicts a stronger inflammatory response and reduced intracellular bacterial growth. A large proportion of these differences are under genetic control: for 804 genes, more than 75% of ancestry effects on the immune response can be explained by a single cis- or trans-acting expression quantitative trait locus (eQTL). Finally, we show that genetic effects on the immune response are strongly enriched for recent, population-specific signatures of adaptation. Together, our results demonstrate how historical selective events continue to shape human phenotypic diversity today, including for traits that are key to controlling infection.
2019-08-29 | GSE136566 | GEO
Project description:Individuals from different populations vary considerably in their susceptibility to immune-related diseases. To understand how genetic variation and natural selection contribute to these differences, we tested for the effects of African versus European ancestry on the transcriptional response of primary macrophages to live bacterial pathogens. 12% of macrophage-expressed genes show ancestry-associated differences in the gene regulatory response to infection, and African ancestry specifically predicts a stronger inflammatory response and reduced intracellular bacterial growth. A large proportion of these differences are under genetic control: for 569 genes, more than 75% of ancestry effects on the immune response can be explained by a single cis- or trans-acting eQTL. Finally, we show that genetic effects on the immune response are strongly enriched for recent, population-specific signatures of adaptation. Together, our results demonstrate how historical selective events continue to shape human phenotypic diversity today, including for traits that are central to coping with infection.
2016-09-06 | GSE81046 | GEO
Project description:(1) In clinical practice and biomedical research populations are often divided categorically into distinct racial and ethnic groups. In reality, these categories comprise diverse groups with highly heterogeneous histories, cultures, traditions, religions, as well as social and environmental exposures. While the factors captured by these categories contribute to clinical practice and biomedical research, the use of race/ethnicity is widely debated. As a response to this debate, genetic ancestry has been suggested as a complement or alternative to this categorization. However, few studies have examined the effect of genetic ancestry, racial/ethnic identity, and environmental exposures on biological processes. Herein, we examine the contribution of self-identification within ethnicity, genetic ancestry, and environmental exposures on epigenetic modification of DNA methylation, a phenomenon affected by both genetic and environmental factors. We typed over 450,000 variably methylated CpG sites in primary whole blood of 573 individuals of Mexican and Puerto Rican descent who also had high-density genotype data. We found that methylation levels at a large number of CpG sites were significantly associated with ethnicity even when adjusting for genetic ancestry. In addition, we found an enrichment of ethnicity-associated sites amongst loci previously associated with environmental and social exposures. Interestingly, one of the strongest associated sites is driven by the Duffy Null blood type variant, demonstrating a new function of the locus in lymphocytes. Overall, the methylation changes associated with race/ethnicity, driven by both genes and environment, highlight the importance of measuring and accounting for both self-identified race/ethnicity and genetic ancestry in clinical and biomedical studies and the benefits of studying diverse populations. (2) In epigenome-wide association studies (EWAS), different methylation profiles of distinct cell-types may lead to false discoveries. We introduce ReFACTor, a method based on principal component analysis (PCA) for the correction of cell-type heterogeneity in EWAS. ReFACTor does not require knowledge of the cell counts, and it obtains improved estimates of the cell-type composition, resulting in improved power and control for false positives in EWAS.
2016-02-29 | GSE77716 | GEO