3882 results for "*geneti*"

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• Genome_Diversity_in_Africa_Project___ancient_samples___standard_libraries

  Given the central importance of Africa to studies of human origins, genetic diversity and disease susceptibility, large-scale and representative characterisation of genetic diversity in Africa is needed. Analyses of ancient DNA from Africa would complement sequencing of modern African populations and provide unique opportunities to transform our understanding of the pre-history of the region. This approach would greatly refine our understanding of population structure and gene flow in Africa and globally, including genetic signatures of ancient admixture. This low coverage sequencing experiment will allow us to test and refine our pipeline for ancient DNA sequencing.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 EGAS00001001182

• Neuroblastoma relapse trio series from the AMC

  The majority of neuroblastoma patients have tumors that initially respond to chemotherapy, but a large proportion of patients will experience therapy-resistant relapses. The molecular basis of this aggressive phenotype is unknown. Whole genome sequencing of 23 paired diagnostic and relapsed neuroblastomas showed clonal evolution from the diagnostic tumor with a median of 29 somatic mutations unique to the relapse sample. Eighteen of the 23 relapse tumors (78%) showed RAS-MAPK pathway mutations. Seven events were detected only in the relapse tumor while the others showed clonal enrichment. In neuroblastoma cell lines we also detected a high frequency of activating mutations in the RAS-MAPK pathway (11/18, 61%) and these lesions predicted for sensitivity to MEK inhibition in vitro and in vivo. Our findings provide a rationale for genetic characterization of relapse neuroblastoma and show that RAS-MAPK pathway mutations may function as a biomarker for new therapeutic approaches to refractory disease.

  Study EGAS00001001183

• G&T-seq: parallel sequencing of the genomes and transcriptomes of single cells

  The ability to simultaneously sequence the genome and transcriptome of the same single cell offersa powerful means to dissect functional genetic heterogeneity at the cellular level. Here we describeG&T-seq, a method for separating and sequencing genomic DNA and full-length mRNA from singlecells. By applying G&T-seq to over 220 single cells we reveal cellular properties that cannot beinferred from DNA or RNA sequencing alone, including associations between DNA copy numbervariation and gene expression dosage. We further demonstrate the detection of coding interchromosomalfusions and single nucleotide variants in both the genomes and transcriptomes ofindividual cells. G&T-seq enables the study of genotype-phenotype associations in single cells, andthe investigation of DNA cell lineage trees of healthy and diseased tissues with transcriptome inferredcell types and states.

  Study EGAS00001001204

• Associations between APOE status and cognitive ability across the lifecourse

  The association between APOE genotype and cognitive function suggests a positive role for the e2 allele and a negative role for the e4 allele. Both alleles have relatively low frequencies in the general population, hence meta-analyses have been based on many small, heterogeneous studies. Here we report the APOE-cognition associations in the largest single analysis to date. APOE status and cognitive ability were measured in 18,337 participants from the Generation Scotland study between 2006 and 2011. The age range was 18-94 years with a mean of 47 (SD 15). Four cognitive domains were assessed: verbal declarative memory (paragraph recall), processing speed (digit symbol substitution), verbal fluency (phonemic verbal fluency), and vocabulary (Mill Hill synonyms). Linear regression was used to assess the associations between APOE genetic status and cognition. Possession of the e4 allele was associated with lower scores on the measures of memory and processing speed in subjects aged >60. Across all age ranges, the e4 allele was linked to better verbal fluency scores. In younger subjects (≤60 years) the e4 allele was linked to higher vocabulary scores. There were no associations between the e2 allele and cognitive ability. As seen in previous meta-analyses, the APOE e4 allele is linked to poorer cognitive performance in the domains of memory and processing speed. By contrast, positive associations were seen between the e4 allele and measures of verbal fluency and vocabulary. All associations were relatively small and, in many cases, nominally significant despite the very large sample size.

  Study EGAS00001001235

• Immunogenomic landscape of hematological malignancies

  We integrated over 8,000 transcriptomes and over 2,000 samples with multilevel genomic data of hematological cancers to investigate how immunological features are linked to cancer subtypes, genetic and epigenetic alterations, and patient survival. For more detailed follow-up analyses in acute myeloid leukemia (AML), single-cell RNA sequencing was performed on 8 AML bone marrow samples at diagnosis to profile the phenotypes of blasts and infiltrating immune cells in different disease subtypes.

  Study EGAS00001004444

• Targets of MEK inhibition in DIPG

  The survival of children with diffuse intrinsic pontine glioma (DIPG) remains dismal, with new treatments desperately needed. In the era of precision medicine, targeted therapies represent an exciting treatment opportunity, yet resistance can rapidly emerge, playing an important role in treatment failure. In a prospective biopsy-stratified clinical trial, we combined detailed molecular profiling (methylation BeadArray, exome, RNAseq, phospho-proteomics) linked to drug screening in newly-established patient-derived models of DIPG in vitro and in vivo. We identified a high degree of in vitro sensitivity to the MEK inhibitor trametinib in samples which harboured genetic alterations targeting the MAPK pathway, including the non-canonical BRAF_G469V mutation, and those affecting PIK3R1 and NF1. However, treatment of PDX models and of a patient with trametinib at relapse failed to elicit a significant response. We generated trametinib-resistant clones in the BRAF_G469V model through continuous drug exposure, and identified acquired mutations in MEK1/2 (MEK1_K57N, MEK1_I141S and MEK2_I115N) with sustained pathway up-regulation. These cells showed the hallmarks of mesenchymal transition, and expression signatures overlapping with inherently trametinib-insensitive primary patient-derived cells that predicted an observed sensitivity to dasatinib. Combinations of trametinib with dasatinib and the downstream ERK inhibitor ulixertinib showed highly synergistic effects in vitro. These data highlight the MAPK pathway as a therapeutic target in DIPG, and show the importance of parallel resistance modelling and rational combinatorial treatments likely to be required for meaningful clinical translation.

  Study EGAS00001004495

• Prenatal lead exposure is associated with decreased cord blood DNA methylation of the glycoprotein VI gene involved in platelet activation and thrombus formation

  Early-life lead exposure impairs neurodevelopment and later exposure affects the cardiovascular system. Lead has been associated with reduced global 5-methylcytosine DNA methylation, suggesting that lead toxicity acts through epigenetic mechanisms. The objective of this study is to clarify how early life lead exposure alters DNA methylation of specific genes, using an epigenomic approach. We measured lead concentrations in urine (gestational week, GW, 8) and erythrocytes (GW 14), using ICP-MS, for 127 pregnant mothers recruited in the MINIMat food and supplementation cohort in rural Bangladesh. Cord blood DNA methylation was analyzed with the Infinium HumanMethylation450K BeadChip and top sites were validated by methylation-sensitive high-resolution melt curve analysis. Maternal urinary lead concentrations (divided into quartiles) showed significant (after adjustment for FDR) inverse associations with methylation at nine CpGs. Three of these sites were in the 5’ end, including the promoter, of glycoprotein IV (GP6); cg18355337 (q=0.029, β=-0.30), cg25818583 (q=0.041, β=-0.18) and cg23796967 (q=0.047, β=-0.17). The methylation in another CpG site in GP6 was close to significant (cg05374025, q=0.057, β=-0.23). The erythrocyte lead concentrations (divided into quartiles) were also inversely associated with CpG methylation in GP6, although this was not statistically significant after FDR-adjustments. Eight CpG sites in GP6 constituted a differentially methylated region in relation to urinary lead (p=0.005, q=0.48) and erythrocyte lead (p=0.007, q=0.46). In conclusion, we found that moderate prenatal lead exposure appear to epigenetically affect GP6, a key component of platelet aggregation and thrombus formation, suggesting a novel link between early lead exposure and cardiovascular disease later in life.

  Study EGAS00001001575

• UK10K NEURO UKSCZ

  In the UK10K project we propose a series of complementary genetic approaches to find new low frequency/rare variants contributing to disease phenotypes. These will be based on obtaining the genome wide sequence of 4000 samples from the TwinsUK and ALSPAC cohorts (at 6x sequence coverage), and the exome sequence (protein coding regions and related conserved sequence) of 6000 samples selected for extreme phenotypes. Our studies will focus primarily on cardiovascular-related quantitative traits, obesity and related metabolic traits, neurodevelopmental disorders and a limited number of extreme clinical phenotypes that will provide proof-of-concept for future familial trait sequencing. We will analyse directly quantitative traits in the cohorts and the selected traits in the extreme samples, and also use imputation down to 0.1% allele frequency to extend the analyses to further sample sets with genome wide genotype data. In each case we will investigate indels and larger structural variants as well as SNPs, and use statistical methods that combine rare variants in a locus or pathway as well as single-variant approaches. These samples have been collected from throughout the UK and Ireland. The samples fall into two main categories, approximately 500 have a full diagnostic work up. A proportion of these are cases with a positive family history of schizophrenia, either collected as sib-pairs or from multiplex kindred's. The second group consist mainly of >300 samples that have been systematically collected within South Wales and in addition to full diagnostic work up have undergone detailed cognitive testing. All samples have obtained a DSM IV diagnosis of schizophrenia or schizoaffective disorder.For further information on this cohort please contact Michael Owen (OwenMJ@cardiff.ac.uk).

  Study EGAS00001000123

• Uterine leiomyoma: DNA methylation, chromatin activity and gene expression

  In this study, we observed the effects of different uterine leiomyoma driver mutations to tumor DNA methylation, chromatin activity and gene expression, to form a comprehensive view on the epigenetic consequences of the mutations.

  Study EGAS00001004499

• DNA methylation and somatic mutations converge on cell cycle and define similar evolutionary histories in brain tumors

  The evolutionary history of tumor cell populations can be reconstructed from patterns of genetic alterations. In contrast to the stability of genetic events, epigenetic states are reversible and sensitive to the microenvironment, prompting the question whether epigenetics can be similarly used to discover tumor phylogeny. We examined the spatial and temporal dynamics of DNA methylation in a cohort of low-grade gliomas and their patient-matched recurrences. Genes upregulated through promoter hypomethylation during malignant progression to high-grade glioblastoma were enriched in cell cycle function, evolving in parallel with genetic alterations that deregulate the G1/S cell cycle checkpoint. Moreover, phyloepigenetic relationships robustly recapitulated phylogenetic patterns inferred from somatic mutations. These findings highlight widespread co-dependency of genetic and epigenetic events throughout brain tumor evolution.

  Study EGAS00001001255