The relationship between DNA methylation, genetic and expression inter-individual variation in untransformed human fibroblasts
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Stephan Busche
PROVIDER: E-GEOD-53261 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Background DNA methylation has long been known to play an essential role in the epigenetic regulation of gene expression and other cellular functions, and has been in some cases linked to genetic variation. While its presence near the transcription start site of a gene has been associated with reduced expression, the variation in methylation levels across individuals, its environmental or genetic causes, and its association with gene expression remain poorly understood. Results We report the joint analysis of sequence variants, gene expression and DNA methylation in primary fibroblast samples derived from a set of 62 unrelated individuals. Approximately 2% of the most variable CpG sites are mappable in cis to sequence variation, usually within 5kb. However, only 5% of those mappable CpG sites also have methylation levels that correlate in cis with a gene's expression level. Methylation and gene expression are often correlated but not always in the expected direction (negative for promoter CpGs, positive for gene body CpGs). Population-level correlation between methylation and expression is strongest in a subset of developmentally significant genes, including all four HOX clusters. The presence and sign of this correlation are best predicted using specific histone marks or DNase hypersensitivity rather than position of the CpG site with respect to the gene, showing that other epigenetic markers are necessary to interpret downstream effects of individual methylation variants. Conclusion Our results indicate strong relationships between gene expression and DNA methylation in untransformed adult human fibroblasts, with considerable involvement of chromatin features and relatively modest involvement of sequence variation. 98 human skin fibroblast samples obtained from Coriell and McGill Cellbank, genotypes were obtained using Illumina HumanOmni 1M Beadchips.
2013-12-11 | E-GEOD-52442 | biostudies-arrayexpress
Project description:Over the past few years, studies of DNA isolated from human fossils and archaeological remains have generated considerable novel insight into the history of our species. Several landmark papers have described the genomes of ancient human ancestors and have demonstrated that contemporary humans harbour genetic material from ancient close relatives, the Neanderthals and Denisovans, and that ancient human individuals are often genetically distinct from nearby extant populations whilst also showing affinities with populations from further afield. Across West Eurasia, there is growing genetic evidence of large-scale, dynamic population movements over the period between 10,000 to 2,000 years ago, such that the ancestry across present-day populations is likely to be a mixture of several ancient groups. Whilst these efforts are bringing the details of West Eurasian prehistory into increasing focus, studies aimed at understanding the processes behind the generation of the current West Eurasian genetic landscape have been limited by the number of populations sampled, or have been either too regional or global in their outlook. Here, using recently described haplotype-based techniques, we present the results of a systematic survey of recent admixture history across Western Eurasia and show that admixture is a universal property across almost all groups. Admixture in all regions except North Western Europe involved the influx of genetic material from outside of West Eurasia, which we date to specific time periods. Within Northern, Western, and Central Europe, admixture tended to occur between local groups during the period 300 to 1200CE. Comparisons of the genetic profiles of West Eurasians before and after admixture show that population movements within the last 1500 years are likely to have maintained differentiation amongst groups. Our analysis provides a timeline of the gene flow events that have generated the contemporary genetic landscape of West Eurasia. 20 individuals from Croatia included as part of an analysis of admixture in West Eurasia
2015-09-17 | E-GEOD-71603 | biostudies-arrayexpress
Project description:We carried out the analyses of chromosome variations between low-grade and high-grade gliomas in Chinese population. We found out the differences in chromosomes, cytobands, genes, pathways and GO functions. To identify the glioma tissue-specific genomic alterations and compare the genomic variations between low-grade and high-grade gliomas.
2015-01-03 | E-GEOD-34888 | biostudies-arrayexpress
Project description:Despite being located at the crossroads of Asia, genetics of the Afghanistan populations have been largely overlooked. It is currently inhabited by five major ethnic populations: Pashtun, Tajik, Hazara, Uzbek and Turkmen. Here we present autosomal from a subset of our samples, mitochondrial and Y- chromosome data from over 500 Afghan samples among these 5 ethnic groups. This Afghan data was supplemented with the same Y-chromosome analyses of samples from Iran, Kyrgyzstan, Mongolia and updated Pakistani samples (HGDP-CEPH). The data presented here was integrated into existing knowledge of pan-Eurasian genetic diversity. The pattern of genetic variation, revealed by structure-like and Principal Component analyses and Analysis of Molecular Variance indicates that the people of Afghanistan are made up of a mosaic of components representing various geographic regions of Eurasian ancestry. The absence of a major Central Asian-specific component indicates that the Hindu Kush, like the gene pool of Central Asian populations in general, is a confluence of gene flows rather than a source of distinctly autochthonous populations that have arisen in situ: a conclusion that is reinforced by the phylogeography of both haploid loci. 24 samples were analysed with the Illumina platform Human660W-Quad v1.0 Genotyping BeadChip and are described herein.
2013-11-04 | E-GEOD-51158 | biostudies-arrayexpress
Project description:Chromosome segregation errors have been linked to DNA damage and genomic rearrangements. Accumulating evidence has shown that catastrophic genomic rearrangements, like chromothripsis, can result from lagging chromosomes undergoing aberrant DNA replication and DNA damage in micronuclei. Detailed characterization of genomic rearrangements resulting from DNA damage in micronuclei has been hampered because of difficulties in culturing daughter cells with DNA damage. Here, we employ a method by which a specific single chromosome is trapped in a micronucleus, followed by transfer to an acceptor cell. Next, stably propagating clonal cell lines with an extra chromosome were established and analyzed by copy number profiling and whole genome sequencing. While non-transformed, p53 proficient and telomerase-immortalized RPE1 cells showed a stable genome following addition of the transferred chromosome, we observed frequent de novo genomic rearrangements in cells derived from the HCT116 colorectal cancer cell line after chromosome transfer. The de novo rearrangements varied from simple deletions and duplications to complex rearrangements. Phase-informative SNPs revealed that the rearrangements specifically occurred on the transferred chromosome. We found that the complex rearrangements recapitulated all features of chromothripsis, including massive oscillation between two copy number states, localization to a single chromosome, random joining of chromosome fragments and non-homologous or micro-homologous repair. We describe an approach that enables the isolation of clonal cell lines with genomic rearrangements and chromothripsis on a specific chromosome in p53 proficient cells. The procedure enables further investigation of the exact mechanism leading to chromothripsis and the analysis of its consequences for cell survival (viability) and cancer development. We analyzed 38 cell clones, originating from HCT116 or RPE1 cells respectively, with Illumina beadchip arrays to test for unique de novo copy number variants and to determine the chromosome affacted by the CNAs.
2015-08-13 | E-GEOD-71978 | biostudies-arrayexpress
Project description:Sakha M-bM-^@M-^S an area connecting South and Northeast Siberia M-bM-^@M-^S is significant for understanding the history of peopling of Northeast Eurasia and the Americas. Previous studies have shown a genetic contiguity between Siberia and East Asia and the key role of South Siberia in the colonization of Siberia. We report the results of a high-resolution phylogenetic analysis of 701 mtDNAs and 318 Y chromosomes from five native populations of Sakha (Yakuts, Evenks, Evens, Yukaghirs and Dolgans) and of the analysis of more than 500,000 autosomal SNPs of 758 individuals from 55 populations, including 40 previously unpublished samples from Siberia. Phylogenetically terminal clades of East Asian mtDNA haplogroups C and D and Y-chromosome haplogroups N1c, N1b and C3, constituting the core of the gene pool of the native populations from Sakha, connect Sakha and South Siberia. Analysis of autosomal SNP data confirms the genetic continuity between Sakha and South Siberia. Maternal lineages D5a2a2, C4a1c, C4a2, C5b1b and the Yakut-specific STR sub-clade of Y-chromosome haplogroup N1c can be linked to a migration of Yakut ancestors, while the paternal lineage C3c was most likely carried to Sakha by the expansion of the Tungusic people. MtDNA haplogroups Z1a1b and Z1a3, present in Yukaghirs, Evens and Dolgans, show traces of different and probably more ancient migration(s). Analysis of both haploid loci and autosomal SNP data revealed only minor genetic components shared between Sakha and the extreme Northeast Siberia. Although the major part of West Eurasian maternal and paternal lineages in Sakha could originate from recent admixture with East Europeans, mtDNA haplogroups H8, H20a and HV1a1a, as well as Y-chromosome haplogroup J, more probably reflect an ancient gene flow from West Eurasia through Central Asia and South Siberia. Our high-resolution phylogenetic dissection of mtDNA and Y-chromosome haplogroups as well as analysis of autosomal SNP data suggests that Sakha was colonized by repeated expansions from South Siberia with minor gene flow from the Lower Amur/Southern Okhotsk region and/or Kamchatka. The minor West Eurasian component in Sakha attests to both recent and ongoing admixture with East Europeans and an ancient gene flow from West Eurasia. 40 samples were analysed with the Illumina platform Human660W-Quad v1.0 and are described herein.
2013-06-26 | E-GEOD-46828 | biostudies-arrayexpress
Project description:Here we present genome-wide high-coverage genotyping data on a panel of 85 human samples from Eurasia that are used in addition to public data in studing the genomic context of a 24 kya old DNA sample from Southern Siberia that was sequenced to the avwerage depth of 1X. 85 samples were analysed with the Illumina platforms Human610-Quad v1.0, HumanHap650Yv3 (HumanHap650Yv3_A) and Human660W-Quad v1.0 Genotyping BeadChips and are described herein.
2013-11-18 | E-GEOD-50727 | biostudies-arrayexpress
Project description:To carry out population genetics analyses of the Arctic gregion we carried out Illumina Bead-Array-based enotyping on 18 samples from Greenland. 19 samples were analysed with the Illumina platform Human660W-Quad v1.0 Genotyping BeadChip and are described herein.
2014-08-28 | E-GEOD-59546 | biostudies-arrayexpress
Project description:This study evaluates genetic and phenotypic variation in the intermediate altitude Calchaquà population living in the Calchaquà Valleys of the Argentinean Andes in the town of Cachi at 2300 m. This study attempts to pinpoint evolutionary mechanisms underlying adaptation to moderate hypoxia at a intermediate altitude. DNA from 24 saliva samples of CalchaquÃes living at 2300 m in Cachi in the Province of Salta in Argentina was genotyped.
2014-04-05 | E-GEOD-56518 | biostudies-arrayexpress
Project description:Here we present genome-wide high-coverage genotyping data on a panel of 75 human samples from Western Balkan region, Europe, that are used in addition to public data in studing the genetic variation of Southern Europe that was sequenced to the avwerage depth of 1X. 70 samples were analysed with the Illumina platform Human660W-Quad v1.0 Genotyping BeadChip and are described herein.
2014-08-22 | E-GEOD-59032 | biostudies-arrayexpress