3931 results for "*geneti*"

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• PSCP_mutation_analysis_in_hESCs

  Many studies over the past 10 years, culminating in the recent report of the International Stem Cell Initiative (ISCI, 2011) have shown that hPSC acquire genetic and epigenetic changes during their time in culture. Many of the genetic changes are non-random and recurrent, probably because they provide a selective growth advantage to the undifferentiated cells. Some are shared by embryonal carcinoma cells, the malignant counterparts of ES cells. The origins of these growth advantages are poorly understood, but may come from altered cell cycle dynamics, resistance to apoptosis or altered patterns of differentiation. Less is known about the nature and consequences of epigenetic changes, but it is likely that these similarly affect hPSC behaviour; e.g., enhanced expression of DLK1, an imprinted gene, is associated with altered hPSC growth (Enver et al 2005). Inevitably, these genetic and epigenetic changes will impact on our ability to use hPSC for regenerative medicine, either because malignant transformation of the undifferentiated cells or their differentiated derivatives to be used for transplantation compromises safety, or because they impede the function of those differentiated derivatives, or because they affect the efficiency with which the undifferentiated cells can be expanded and differentiated into desired cell types. Focusing initially upon the existing clinical grade hESC lines, later moving to iPSC, we will Consolidate and extend knowledge of the rate, type and functional impact of the genetic variations that occur during hPSC culture. We will use whole genome and exome sequencing as well as SNP arrays, together with clonal analysis and other cytogenetics techniques. Common changes will be compared with those found in the normal human population, at low frequency in the original cell population or observed during iPSC generation in the HIPSCI project currently based at the WTSI. These studies will provide a better understanding of the range of genetic changes that occur in hPSC beyond the CNVs already identified. In conjunction with cancer genome resources and expertise at WTSI, bioinformatic analyses of these hPSC data will allow us to assess potential impact on hPSC behaviour pertinent to applications in regenerative medicine, notably the likelihood that specific changes arising in undifferentiated PSC cultures may be associated with potential malignant transformation of differentiated progeny. This data is part of a pre-publication release. For information on the proper use of pre-publication data shred by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/

  Study EGAS00001001561

• The_genetic_evolution_of_precursor_lesions_in_pancreatic_cancer

  Mapping genetic evolution of pancreatic cancer precursor lesions such as IPMNs and PanINs.

  Study EGAS00001001573

• Super enhancers define regulatory subtypes and cell identity in neuroblastoma

  Half of the children diagnosed with neuroblastoma have high-risk disease, disproportionately contributing to overall childhood cancer-related deaths. In addition to recurrent gene mutations, there is increasing evidence supporting the role of epigenetic deregulation in disease pathogenesis. Yet, comprehensive cis-regulatory network descriptions from neuroblastoma tissues are lacking. Here, using genome-wide H3K27ac profiles across 60 neuroblastomas, covering the different clinical and molecular subtypes, we identified four major super enhancer-driven epigenetic subtypes and their underlying master regulatory networks. Three of these subtypes recapitulated known clinical groups, namely MYCN amplified, MYCN non-amplified high-risk and MYCN non-amplified low-risk neuroblastomas. The fourth subtype, exhibiting mesenchymal characteristics, shared features with multipotent Schwann cell precursors, was induced by RAS activation and enriched in relapsed disease. Notably, CCND1, a disease essential gene, was regulated by both mesenchymal and adrenergic regulatory networks converging on distinct super-enhancer modules. Together, this reveals subtype-specific super-enhancer regulation in neuroblastoma.

  Study EGAS00001004551

• International Genetics of Parkinson Disease Progression (IGPP) Consortium GWAS Summary Results

  To characterize how genetic variation influences the progression of Parkinson’s disease to dementia, which is a major determinant for quality of life, we performed a longitudinal genome-wide survival study (GWSS). Risk profile analysis was performed with a novel polygenic hazard score in longitudinal cohorts in the International Genetics of Parkinson Disease Progression (IGPP) Consortium.

  Study EGAS00001005110

• Papuan_Genotyping

  By array based genotyping of indigenous individuals from different areas of Papua New Guinea, this project aims to provide the most comprehensive overview thus far of population structure and history in this part of the world. Papuans represent a key component in the current understanding of human history outside of Africa. Additionally, PNG harbours enormous cultural and linguistic diversity. Genotyping of diverse individuals, combined with previously generated whole-genome sequencing data, will allow the study of general patterns of population structure, the degree of genetic differentiation between groups, the extent of external gene flow into PNG and the genetic relationships to Australian Aboriginals.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 (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/

  Study EGAS00001001587

• Integrated genomic characterization of IDH1 mutant Glioma malignant progression

  Gliomas represent approximately 30% of all central nervous system tumors, and 80% of malignant brain tumors. To understand the molecular mechanisms underlying the malignant progression of low-grade Isocitrate Dehydrogenase 1 (IDH1) mutant gliomas, we studied paired tumor samples from 41 patients, comparing higher-grade, progressed samples to their lower-grade counterparts. Integrated genomic analyses, including whole-exome sequencing, copy number, gene expression and DNA methylation profiling, demonstrated non-linear clonal expansion of the original tumors and identified oncogenic pathways driving progression. These include activation of the MYC and RTK-RAS-PI3K pathways, up-regulation of the FOXM1- and E2F2-mediated cell cycle transition genes, as well as epigenetic silencing of developmental transcriptional factors bound by Polycomb repressive complex 2 in human embryonic stem cells. Our results not only provide mechanistic insight into the genetic and epigenetic mechanisms driving glioma progression but also identify inhibition of the bromodomain and extra-terminal (BET) family as a potential therapeutic approach.

  Study EGAS00001001588

• Epigenetic dynamics of monocyte to macrophage differentiation

  Monocyte to macrophage differentiation involves major biochemical and structural changes in non-dividing cells. In order to elucidate the role of gene regulatory changes during this process, we used high-throughput sequencing to analyze the complete transcriptome and epigenome of human monocytes that were isolated by elutriation and differentiated in vitro by addition of MCSF in serum-free medium. We also investigated the effect of loading the macrophages with modified LDL. We found that many mRNAs and miRNAs were significantly up- or downregulated during differentiation. While there was no correlation between gene expression and DNA methylation changes at transcription start sites, we identified a large number of intra- and intergenic regions that rapidly lost DNA methylation, became nucleosome-free and gained histone marks indicative of active enhancers. Loading of macrophages with modified LDL caused gene expression changes, but no chromatin changes. In summary, our results demonstrate that monocyte to macrophage differentiation is associated with rapid, highly targeted epigenetic changes, whereas lipid uptake mainly affects regulatory circuits of soluble factors.

  Study EGAS00001001595

• Malignant pheochromocytomas/paragangliomas harbor mutations in transport and cell adhesion genes

  One out of ten patients with pheochromocytoma (PCC) and paraganglioma (PGL) develop malignant disease. Today there are no reliable pathological methods to predict malignancy at the time of diagnosis. Tumors harboring mutations in the succinate dehydrogenase subunit B (SDHB) gene often metastasize but the sequential genetic events resulting in malignant progression are not fully understood. The aim of this study was to identify somatic mutations that contribute to the malignant transformation of PCC/PGL. We performed pair-wise (tumor-normal) whole-exome sequencing to analyze the somatic mutational landscape in five malignant and four benign primary PCC/sympathetic PGL (sPGL), including two biological replicates from each specimen. In total, 225 unique somatic mutations were identified in 215 genes, with an average mutation rate of 0.54 mutations/megabase. Malignant tumors had a significantly higher number of mutations compared to benign tumors (p<0.001). Three novel genes were identified as recurrently mutated; MYCN, MYO5B and VCL, and mutations in these genes were exclusively found in malignant sPGL tumors. Mutations in the MYO5B gene could be verified in two publicly available data sets. A gene ontology analysis of mutated genes showed enrichment of cellular functions related to cytoskeletal protein binding, myosin complex, and motor activity, many of which had functions in Rab and Rac/Rho GTPase pathways. Conclusively, we have identified recurrent mutations in genes related to intracellular transport and cell adhesion, and we have confirmed recurrent mutations of MYO5B in PCC/PGL cases with malignant potential. Our study suggests that deregulated Rab and Rac/Rho pathways may be important in PCC/PGL tumorigenesis.

  Study EGAS00001001601

• Genetic and expression landscape of Waldenstrom macroglobulinemia

  Exome analyses for the identification of somatic mutation in Waldenstrom macroglobulinemia by comparison of tumor and CD3+(germ line control) population in 16 patients. transcription profiling of a series of Waldenstrom macroglobulinemia samples

  Study EGAS00001003603

• Exome sequencing of patients with rare neurological disorders

  Exome sequencing of patients and their families with diverse rare neurological disorders. Some families have prior linkage data identifying a specific chromosomal interval or interest, other families do not have linkage data available. Many of these families come from special populations whose demography or preference for consanguineous marriages make them particularly tractable for genetic studies.

  Study EGAS00001000159