3329 results for "*geneti*"

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• Revealing active mutational processes in tumours using DigiPico/MutLX at unprecedented accuracy

  Active mutational processes in a tumor result in genetic micro-heterogeneity that can determine the tumor’s evolutionary trajectory. Identification of these processes by studying micro-heterogeneity can unveil novel aspects of tumor evolution with potential therapeutic implications. Such studies, however, are inherently problematic because of the discovery of excessive false positive mutations. Here we report the optimization and validation of a robust whole genome sequencing and analysis pipeline (DigiPico/MutLX) that virtually eliminates false positive results. Using our method, we identified, for the first time, a sub-clonal local hyper-mutation (kataegis) event in a recurrent ovarian carcinoma, which was unidentifiable from the bulk WGS data of the same tumor. Overall, we propose DigiPico/MutLX method as a powerful framework for the reliable study of genetic micro-heterogeneity in tumor and normal tissues.

  Study EGAS00001003555

• Whole genome sequencing with linked reads of pediatric glioblastoma samples

  Pediatric glioblastoma (pGBM) is a lethal cancer with no effective therapies. To understand mechanisms of tumor evolution in this cancer, we performed whole genome sequencing with linked reads on longitudinally resected pGBM samples. Our analyses showed that all diagnostic and recurrent samples were collections of genetically diverse subclones. Clonal composition rapidly evolved at recurrence, with less than 8% of non-synonymous single nucleotide variants being shared in diagnostic-recurrent pairs. In order to track the origins of the mutational events we observed in pGBM, we generated whole genome datasets for two patients and their parents. These trios showed that genetic variants could be (i) somatic, (ii) inherited from a healthy parent, or (iii) arose de novo in the germlines of pGBM patients. Analysis of variant allele frequencies supported a model of tumor growth involving slow-cycling cancer stem cells that give rise to fast-proliferating progenitor-like cells and to non-dividing cells. Interestingly, radiation and anti-mitotic chemotherapeutics did not increase overall tumor burden upon recurrence. These findings support an important role for slow-cycling stem cell populations in contributing to recurrences, since slow-cycling cell populations are expected to be less prone to genotoxic stress induced by these treatments and to accumulate few mutations. Our results highlight the need for new targeted treatments that account for the complex functional hierarchies and genomic heterogeneity of pGBM.

  Study EGAS00001003432

• Egyptref: An integrated personal and population-based Egyptian genome reference

  North African individuals are not represented in current genetic data sets. To address this issue, we generated an integrated personal and population-based Egyptian genome reference called Egyptref. Towards this end, we performed a human de novo assembly of an Egyptian individual using long PacBio reads (99x genome coverage) and polished it using Illumina short reads (90x). Variants were phased using 10x Genomics linked reads (80x). This personal genome was complemented with whole genome sequencing-based variant data of 109 further Egyptians and mitochondrial haplogroups from mtDNA sequencing of 326 further Egyptians (of which 100 individuals from EGAD00001001372/EGAD00001001380) to obtain a population-based genome. We used Egyptref for assessing the impact of genetic variation, e.g. by integration of blood RNA sequencing data of the assembly individual.

  Study EGAS00001004303

• Genotype data from 'Evidence of the interplay of genetics and culture in Ethiopia'

  Study EGAS00001005171

• Evolutionary predictability of genetic versus non genetic resistance to anticancer drugs in melanoma

  Therapy resistance arises from heterogeneous drug-tolerant persister cells or minimal residual disease (MRD) through genetic and nongenetic mechanisms. A key question is whether specific molecular features of the MRD ecosystem determine which of these two distinct trajectories will eventually prevail. We show that, in melanoma exposed to MAPK therapeutics, emergence of a transient neural crest stem cell (NCSC) population in MRD concurs with the development of nongenetic resistance. This increase relies on a GDNF-dependent signaling cascade, which activates the AKT survival pathway in a focal adhesion kinase (FAK)-dependent manner. Ablation of the NCSC population through FAK inhibition delays relapse in patient-derived tumor xenografts. Strikingly, all tumors that ultimately escape this treatment exhibit resistance-conferring genetic alterations and increased sensitivity to ERK inhibition. These findings identify an approach that abrogates the nongenetic resistance trajectory in melanoma and demonstrate that the cellular composition of MRD deterministically imposes distinct drug resistance evolutionary paths.

  Study EGAS00001005314

• The Asian Diversity Project: genotyping of 37 Asian populations and ethnic groups

  The Asian Diversity Project (ADP) assembled 37 cosmopolitan and ethnic minority populations in Asia that have been densely genotyped across over half a million markers to study patterns of genetic diversity and positive natural selection.

  Study EGAS00001002100

• Genetic determinants of glycated hemoglobin levels in the Greenlandic Inuit population

  We recently showed that a common genetic variant leads to a remarkably increased risk of type 2 diabetes (T2D) in the small and historically isolated Greenlandic population. Motivated by this, we aimed at investigating the genetic determinants for glycated hemoglobin (HbA1C). We found no novel associations but saw that for 10 out of 15 known HbA1C loci that the effects in Greenlandic Inuit were similar to previously reported. One locus, ANK1, showed a significant ancestral population specific effect. Our results shed light on the genetics effects across ethnicites.

  Study EGAS00001002641

• UK Biobank whole cohort directly genotyped and imputed data (~500,000 participants)

  Genotype data is available for all 500,000 participants in the UK Biobank cohort. Genotyping has been performed using the Affymetrix UK BiLEVE Axiom array on an initial 50,000 participants and the remaining 450,000 participants have been genotyped using the Affymetrix UK Biobank Axiom® array. The two arrays are extremely similar (with over 95% common content).Quality control and imputation (to over 90 million SNPs, indels and large structural variants) has been performed by a collaborative group headed by the Wellcome Trust Centre for Human Genetics.The following data are available:* A clean set of QC’ed genotype calls* Confidence values that a genotype call is correct* Intensity data to generate cluster plots* Extensive QC information regarding SNPs and samples including SNP metrics, batch effects, population structure and relatedness* Imputed dataFor further information, please refer to the UK Biobank website

  Study EGAS00001002399

• 20_Matched_Pair_Breast_Cancer_Genomes

  We propose to definitively characterise the somatic genetics of 20 breast cancers through generation of comprehensive catalogues of somatic mutations by high coverage genome sequencing coupled with integrated transcriptomic data.

  Study EGAS00001000170

• H3Africa - Collaborative African Genomics Network

  Genomic studies have become one of the potential tools that could aid in the understanding of disease. HIV disease progression and active TB infection have been studied using these genomic methods to interrogate host factors associated with these diseases and their progression. Prior work has focused on adult populations and limited African cohorts. The Collaborative African Genomics Network aims to fill this gap by conducting HIV and TB disease mapping studies in African children to understand how genetic variation impacts disease progression through the use of genomic technologies.

  Study EGAS00001002656