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PROVIDER: PRJNA647459 | ENA |
REPOSITORIES: ENA
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Project description:Exome sequencing of (YRI) Yoruba in Ibadan Nigeria HapMap population
| PRJNA59839 | ENA
Project description:Ethnic differences in human DNA methylation have been shown for a number of CpG sites, but the genome-wide patterns and extent of these differences are unknown. In addition, whether the genetic control of polymorphic DNA methylation is population-specific has not been investigated. Here we measure DNA methylation near the transcription start sites of over 14,000 genes in 180 cell lines derived from one African and one European population. We find population-specific patterns of DNA methylation at over a third of all genes. Furthermore, although the methylation at over a thousand CpG sites is heritable, these heritabilities are also distinctly different between populations, suggesting extensive divergence in the genetic control of DNA methylation. In support of this, genetic mapping of DNA methylation reveals that there is also little overlap in genetic associations between populations. This population-specificity is supported by the patterns of DNA methylation in several hundred brain samples, suggesting it holds in vivo and across tissues. These results suggest that DNA methylation is highly divergent between populations, and that this divergence may be due in large part to complex epistasis or gene x environment interactions. Genomic DNA from 180 lymphoblastoid cell lines were bisulphite converted and hybridized, along with 8 additional technical replicates, to the Illumina Infinium HumanMethylation27 Beadchip v1.2 for genome-wide DNA methylation profiling. The cell lines were derived from two HapMap populations: 'CEPH (Utah residents with ancestry from northern and western Europe)' (CEU) and 'Yoruba in Ibadan, Nigeria' (YRI).
2012-01-30 | E-GEOD-27146 | biostudies-arrayexpress
Project description:Noncoding variants play a central role in the genetics of complex traits, but we still lack a full description of the main molecular pathways through which they act. Here we used molecular data to quantify the contribution of cis-acting genetic effects at each major stage of gene regulation from chromatin to proteins, within a population sample of Yoruba lymphoblastoid cell lines (LCLs). We performed 4sU metabolic labeled transcripts in 65 YRI LCLs to identify genetic variants that affect transcription rates. As expected, we found an important contribution of genetic variation via chromatin, contributing â¼65% of eQTLs (expression Quantitative Trait Loci). The remaining eQTLs, which are not asso- ciated with chromatin-level variation, are highly enriched in transcribed regions, and hence may affect expression through co- or post-transcriptional processes. International HapMap lymphoblastoid cell lines (LCLs) derived from YRI (Yoruba in Ibadan, Nigeria); We adapted the 4sU labelling method from (PMID 21516085). Briefly, cell cultures were grown to log phase in volumes sufficient to yield about 300 ng of 4sU-labeled RNA. Cells were incubated with 4sU for the required length of time (0, 30, or 60 minutes), then washed, pelleted, and frozen. Total RNA was extracted, and 4sU-labeled RNA was separated from total RNA using a bead-based biotin-streptavidin purification protocol. We sequenced metabolic labeled transcripts in 65 YRI LCLs 30 minutes and 60 minutes after incubation.
2016-03-29 | E-GEOD-75220 | biostudies-arrayexpress
Project description:Genome variability analysis of Yoruba in Ibadan, Nigeria (NA18507) by SOLiD mediated whole genome re-sequencing
| PRJNA28957 | ENA
Project description:Homo sapiens NA18906, YORUBAN IN IBADAN, NIGERIA, Genome sequencing and assembly
| PRJNA604213 | ENA
Project description:<p>In 1991 collaboration between researchers at Indiana University School of Medicine and the University of Ibadan, Ibadan, Nigeria established the Indianapolis-Ibadan Dementia Project. It is a longitudinal, prospective population-based comparative epidemiological study of the prevalence and incidence rates and risk factors of Alzheimer's disease and other age associated dementias. The project compares samples of community-dwelling elderly (age > 70 years) African Americans living in Indianapolis to Yoruba living in Ibadan, Nigeria, employing the same research design, methods, and investigators. It initially reported significantly lower prevalence rates of disorders in the Yoruba compared to the African Americans. In subsequent waves of the study (1994-1995, 1997-1998) incidence rates, rates of newly diagnosed cases, were also found to be significantly lower in the Yoruba. In genetic studies, the frequency of the APOE 4 allele was about the same in the two groups. APOE 4 was a significant risk factor for Alzheimer's disease and dementia in the Americans, while no association was found for the Yoruba. The APOE 2 allele appears to be protective in the Americans, but not the Yoruba. A constellation of factors often associated with vascular risk including a history of hypertension, diabetes, and high cholesterol levels is less common in the Yoruba than in the American group. An interaction was observed between cholesterol, APOE genotype and Alzheimer's disease in both study groups.</p> <p>In 2001-2002 survivors of the original cohort were once again evaluated (N~800 in each site) and 2,000 additional individuals age 70 years and older were enrolled in each site. Blood samples were collected from approximately 1,500 study participants in each site for genetic studies and analysis of biochemical risk factors for vascular disease. Subsequent waves of field work were conducted in 2004, 2007, 2009, and 2011. This fieldwork followed the classic two-stage study design. The study design involves an in-home screening interview with the study participant, which includes a cognitive assessment, medical history and current medications, brief neurological examination, height and weight, blood pressure measurement and assessment of social involvement. There is also a screening interview with a close relative of the study participant to assess activities of daily living, personality change, and medical history of the study participant. On the basis of the screening interview a sample of study participants (N~500 in each site) is selected for a full clinical diagnostic dementia work up which includes a neurological test battery, extensive interview with a family member and examination by a clinician. Diagnoses are made in a consensus diagnosis conference using the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III R) and International Classification of Diseases 10th Revision (ICD-10) for dementia. The criteria of the National Institute for Neurological and Communicative Disease and Stroke-Alzheimer's Disease and Related Disorders Association were used to diagnose possible and probable Alzheimer's disease.</p> <p>The focus of the study is risk factors for dementia and Alzheimer's disease, but also of particular importance is the question of mild cognitive impairment. This refers to the condition of having some decline in cognition but the decline is not sufficient to meet the criteria for dementia. We have studied this over the course of this project. In follow up studies of individuals who have this diagnosis about one third of them are better at follow up, about a third are about the same, and about a third decline more to meet the criteria for dementia. This is a very important issue for researchers because the ultimate goal of the research is to figure out how to identify the individuals who will definitely progress to dementia. If there are clear identifiers, it would be possible to make interventions, while individuals still function well, and possibly prevent the development of dementia altogether or delay the onset significantly. This is crucial because at the moment individuals usually do not enter into the medical care system until the dementia symptoms are quite severe, and the pathological damage to the brain cannot be undone.</p>
| phs000378 | dbGaP
Project description:Pseudouridine (Ψ) is one of the most abundant modifications in cellular RNA. However, its function remains elusive, mainly due to the lack of highly sensitive and accurate detection methods. To address this challenge, we introduced 2-bromoacrylamide-assisted cyclization sequencing (BACS) for quantitative profiling of Ψ at single-base resolution. Based on novel bromoacrylamide cyclization chemistry, BACS enables a Ψ-to-C transition. Compared to previous methods, BACS allowed the precise identification of Ψ positions, especially in densely modified Ψ regions and consecutive uridine sequences. BACS successfully detected all known Ψ sites in human rRNA and spliceosomal snRNAs and generated the first quantitative Ψ map of human snoRNA and tRNA. Furthermore, BACS simultaneously detected adenosine-to-inosine (A-to-I) editing sites and N1-methyladenosine (m1A). Depletion of three key pseudouridine synthases (PUS) enabled us to elucidate the targets and sequence motifs of TRUB1, PUS7, and PUS1 in HeLa cells. We further applied BACS to Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) and identified a highly abundant Ψ114 site in EBER2. Surprisingly, applying BACS to a panel of RNA viruses demonstrated the absence of Ψ in their viral transcripts or genomes, shedding light on differences in pseudouridylation between virus families. We anticipate BACS to serve as a powerful tool to uncover the biological importance of Ψ in future studies.
2024-07-31 | GSE241849 | GEO
Project description:LUHYA IN WEBUYE, KENYA BACs Genome sequencing and assembly
| PRJNA647461 | ENA
Project description:CIDR_Genome Wide Association study of Yoruba in Nigeria
| PRJNA75989 | ENA
Project description:CIDR_Genome Wide Association study of Yoruba in Nigeria
| PRJNA75991 | ENA