3334 results for "*geneti*"

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• Profiling_heterogeneity_in_Human_derived_IPSC_neurons

  The impact of genetic variants on molecular pathways that give rise to neurodegenerative diseases such as Alzheimer’s and Parkinson’s is best elucidated in the appropriate cell types and molecular contexts. Existing studies have focused on bulk profiling of mixed cell types, but have ignored assaying genetic effects across development and cell differentiation. At the core of this proposal is the idea to use single-cell assays to study genetic effects during differentiation of dopaminergic and cortical neurons to identify the sequence of molecular events from variants to healthy and diseased cell states in a cell-specific manner. 1) This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute please see http://www.sanger.ac.uk/datasharing/

  Study EGAS00001002885

• A whole genome analysis of single fetal human stem cells from the liver and the intestine

  Mutations of embryonic and fetal origin have the potential to affect a large proportion of adult cells and may alter cancer predisposition or lead to genetic disease syndromes. We have recently shown that human adult-stem cells progressively acquire approximately 40 novel tissue-specific mutations per year throughout postnatal life. Prenatal mutation rates are as yet unknown. Here we determined genome-wide mutation patterns of single stem cells in human development by sequencing of clonally expanded intestinal and liver organoid cultures of 2nd trimester human foetuses. Our results show that mutation rates in fetal stem cells are significantly higher than in adult stem cells.

  Study EGAS00001002886

• To determine the mutational impact of the in vitro culture, clonal human adult and pluripotent stem cell lines were subjected to a second clonal step after 3 months of culture. These subclones were whole genome sequenced to identify all the mutations that accumulated during the 3 month culture period.

  Genetic changes acquired during culture pose a potential risk for the successful application of stem cells. To assess the risk of in vitro expansion on mutation accumulation we have performed whole genome sequencing of clonally expanded human induced pluripotent stem cells (iPS cells) and adult stem cells (ASCs) to identify all mutations that accumulated over a fixed culture period. We find that ASCs acquire more single nucleotide variants (SNVs) and indels per population doubling than the iPS cells. When compared with ASCs, iPS cells are more vulnerable to mutations in genes and promoters. Mutational analysis revealed a clear in vitro induced mutational signature that is irrespective of stem cell type. This in vitro signature is characterized by C to G transversions that are probably caused by oxidative stress. Additionally, we observed stem cell specific mutational signatures and differences in transcriptional strand bias, indicating differential activity of DNA repair mechanisms between stem cell types in culture. In conclusion, in vitro culture induces mutation accumulation in iPS cells and ASCs. Culture under low-oxygen tension may help to reduce the number of culture-induced mutations.

  Study EGAS00001002955

• GoDARTS T2D-GENES Exome Sequencing Study is a subset of the ~52,000 Type 2 diabetes exome sequencing project.

  The GoDARTS T2D-GENES Exome sequencing study is a subset of a larger Type 2 Diabetes Exome Sequencing project. This effort is a collaboration of six consortia with various funding mechanisms that have joined together to investigate genetic variants for type 2 diabetes (T2D) using the largest T2D case/control sample set compiled to date and includes samples from: T2D-GENES, GoT2D, ESP, SIGMA T2D, LuCAMP, and ProDIGY. This data generated from the Genetics of Diabetes and Audit Research Tayside Study (GoDARTS) cohort was part of the T2D-GENES (Type 2 Diabetes Genetic Exploration by Next-generation sequencing in multi-Ethnic Samples) consortium, which is a NIDDK-funded international research consortium that seeks to identify genetic variants for T2D through multiethnic sequencing studies. Sequencing for the GoDARTS study was performed at the Broad Institute using Illumina Rapid Capture on Illumina HiSeq machines.

  Study EGAS00001002937

• Botswana 15 autosomal unlinked microsatellites

  Population structure was investigated in 990 Botswana individuals according to ethno-linguistics, Bantu and Khoisan, and geography (the nine administrative districts) using the AmpFLSTR Identifiler autosomal microsatellite markers. Genetic diversity and forensic parameters were calculated for the overall population, and according to ethno-linguistics and geography. The overall combined power of exclusion (CPE) was 0.9999965412 and the combined match probability 6,28 x 10-19. CPE was highest for the Khoisan Tuu ethnolinguistic group and the Northeast District at 0.9999582029 and 0.9999922652 respectively. CMP ranged from 6.28 x 10-19 (Khoisan Tuu) to 1,02 x 10-18 (Northwest district). Using pairwise genetic distances (FST), analysis of molecular variance (AMOVA), factorial correspondence analysis (FCA), and the unsupervised Bayesian clustering method found in STRUCTURE and landscape genetics software TESS, ethno-linguistics were found to have a greater influence on population structure than geography. FCA showed clustering between Bantu and Khoisan, and within the Bantu. This Bantu sub-structuring was not seen with STRUCTURE and TESS, which detected clustering only between Bantu and Khoisan. The patterns of population structure revealed highlight the need for regional reference databases that include ethno-linguistic and geographic location information. These markers have important potential for bio-anthropological studies as well as for forensic applications.

  Study EGAS00001002380

• Population_dynamics_in_abnormal_haematopoiesis

  Background: Our recent study has made direct insight into the clonal dynamics of blood cell production in an unperturbed setting in a human. Using whole genome sequencing to track acquired somatic mutations, we were able to construct a phylogenetic tree of different stem and progenitor cells and used this tree to determine the dynamics of mature blood cell production in longitudinal samples. These data set the baseline for understanding population dynamics in abnormal haematopoiesis, and how malignant clones outcompete their normal counterparts to drive haematological malignancies. Aim: This study will measure population dynamics in abnormal human haematopoiesis in patients with clonal blood stem cell disorders. Methods: From patient bone marrow or peripheral blood, we have isolated colonies grown from single blood stem cells/progenitors. Colony DNA will be analysed by whole-genome sequencing to build (or populate) a phylogenetic tree to determine clonal relationships and track stem cell contribution to mature blood cell production. These data will also reveal disease-associated genomic features (mutational burden and mutational signatures) in haematopoietic cells.

  Study EGAS00001003181

• Analysis of IDHwt-glioblastoma samples from paired primary and recurrent tumor samples

  IDHwt-glioblastomas rapidly recur after initial treatment. To study genetic evolution in glioblastoma, we analyzed whole genomes of 21 pairs of primary and recurrent tumor samples using next generation sequencing. In addition we sequenced RNA from 16 tumor pairs and a panel of 50 glioma-associated genes in tumor pairs from 43 patients (including 14 of the 21 patients included in the WGS discovery set). Glioblastoma subtypes were determined using 450k/EPIC methylation arrays. This study was supported within the e:med program of the German Ministry of Education and Research (BMBF) by the collaborative research project ‘SYS-GLIO - Systems-based prediction of the biological and clinical behavior of gliomas’ (https://www.sys-med.de/de/demonstratoren/sys-glio/) This study is part of the Heidelberg Center for Personalized Oncology - HIPO-043

  Study EGAS00001003184

• Low frequency and rare coding variation contributes to multiple sclerosis risk

  Multiple sclerosis is a common, complex neurological disease, where almost 20% of risk heritability can be attributed to common genetic variants, including >230 identified by genome-wide association studies. Multiple strands of evidence suggest that the majority of the remaining heritability is also due to the additive effects of individual variants, rather than epistatic interactions between these variants, or mutations exclusive to individual families. Here, we show in 68,379 cases and controls that as much as 5% of this heritability is explained by low-frequency variation in gene coding sequence. We identify four novel genes driving MS risk independently of common variant signals, which highlight a key role for regulatory T cell homeostasis and regulation, IFNγ biology and NFκB signaling in MS pathogenesis.

  Study EGAS00001003195

• Genetic characterization of B-cell prolymphocytic leukemia: a hierarchical prognostic model involving MYC and TP53 abnormalities - WXS

  B-PLL is a rare disease, whose molecular pathology is largely unknown. We report here the cytogenetic and molecular findings in a large series of 34 B-PLL. Karyotype (K) was complex (≥3 abnormalities) in 73%, and highly complex (HCK≥5) in 45%. The most frequent chromosomal aberrations were: translocation targeting the MYC gene [t(MYC)] (62%), 17p deletion including TP53 gene (38%), trisomy 18/18q (30%), 13q14 deletion (29%), trisomy 3 (24%), trisomy 12 (24%) and 8p deletion (23%). Whole-Exome Sequencing performed in 16 patients revealed recurrent mutations in TP53 (6/16, 38%), MYD88 (n=4), BCOR (n=4), MYC (n=3), SF3B1 (n=3), FAT1 (n=3), SETD2 (n=2), CHD2 (n=2), CXCR4 (n=2) and BCLAF1 (n=2). The main group of patients (21/34, 62%) had a t(MYC) associated with a higher percentage of prolymphocytes (p=0.03), CD38 expression (p<0.001), lower K complexity (p=0.0004), mutations in MYC and in genes involved in RNA metabolism and chromatin remodeling. Principal component analysis of gene expression data showed that patients with t(MYC) clustered together. A second group with MYC gain (5/34, 15%), was associated with HCK≥5 (p=0,01) and trisomy 3 (p=0,008). Altogether, 26/34 patients (76%) had a MYC activation, translocation or gain, that were mutually exclusive. We identified 3 distinct cytogenetic prognostic groups (p=0.0006): lower risk: absence of MYC activation (median not reached); intermediate risk: MYC activation without del17p (125 months); high risk: MYC activation + del17p (11 months). Our results show that cytogenetic analysis is a useful diagnostic tool in B-PLL that improves prognostic stratification.

  Study EGAS00001003275

• Genomics of enteropathy associated T cell lymphoma (EATL)

  Enteropathy-associated T cell lymphoma (EATL) is a lethal and the most common neoplastic complication of celiac disease. In this study, we applied whole exome sequencing in 69 EATL tumors to define the genetic landscape of EATLs. The most frequently mutated gene in EATL was SETD2 (32% of cases), with loss of function mutations comprising a large proportion (41%) of those mutations. The JAK-STAT pathway was the most frequently mutated signaling pathway, with mutations in STAT5B being the most common, followed by JAK1, JAK3, STAT3, and the negative regulator of the pathway, SOCS1. We also identified mutations in NRAS and KRAS, as well as TP53 and TERT. Interestingly, the two types of EATL had highly overlapping genetic alterations indicating shared mechanisms underlying their pathogenesis. Gene expression analysis of the two types of EATL identify robust differences in transcriptional profiles. We further modeled the effects of SETD2 loss in vivo by developing a T cell specific knockout mouse model. These mice manifested an expansion of γδ T cells that identify novel roles for SETD2 in T cell development and lymphomagenesis. Together, our data render the most comprehensive genetic portrait yet of this uncommon but lethal disease, and may inform future classification schemes.

  Study EGAS00001001954