Similar Datasets
Project description:Comparison between groups of monozygotic (MZ) and dizygotic (DZ) twins enables an estimation of the relative contribution of genetic, shared and non-shared environmental factors to phenotypic variability. Using DNA methylation profiling of ~20,000 CpG sites as a phenotype, we have examined discordance levels in multiple tissues in neonatal twins. MZ twins exhibit a wide range of within-pair differences at birth, but show discordance levels generally lower than DZ pairs. Within-pair methylation discordance was lowest in CpG islands in all twins and increased as a function of distance from islands. This was largely independent of distance from transcriptional start site in promoters without CpG islands. Variance component decomposition analysis of DNA methylation in MZ and DZ pairs revealed a low mean heritability across all tissues, although a wide range of heritabilities was detected for specific genomic CpG sites. The largest component of variation was attributed to the combined effects of non-shared intrauterine environment and stochastic factors. Regression analysis of methylation on birth weight revealed a general association between methylation of genes involved in metabolism and biosynthesis, providing further support for epigenetic change in the previously described link between low birth weight and increasing risk for cardiovascular, metabolic and other complex diseases. Finally, comparison of our data with that of several older twins, revealed little evidence for genome-wide epigenetic drift with increasing age. This is the first study to analyse DNA methylation on a genome scale in twins at birth, further highlighting the importance of the intrauterine environment on shaping the neonatal epigenome. Data from cord blood mononuclear cells (CBMCs), human umbilical vascular endothelial cells (HUVECs) and placenta from 22 MZ and 11 DZ pairs with one replicate sample
2012-07-17 | E-GEOD-36642 | biostudies-arrayexpress
Project description:Our results revealed critical chromatin remodeling events and highlight the discordance between chromatin accessibility and transcriptional activity. We further demonstrate that the differential epigenetic modifications and transcription factor (TF) activities may play a critical role in regulating gene expression, and account for the observed variations in gene expression despite similar chromatin landscapes.
2023-10-28 | GSE246440 | GEO
Project description:Multiple synchronous and metachronous lung tumors are frequently encountered in patients with lung cancer. For treatment purposes it is important to determine, whether or not tumors are clonally related. In other words, whether multiple tumors in a patient are either metastases or multiple primaries. Previous reports show considerable discordance between histopathological and molecular comparison of tumor pairs. The purpose of this study is to compare genome-wide copy number analysis to the classical histological and clinicopathological routine for clonality analysis in a prospective cohort of patients with synchronous or metachronous tumors, of which at least one site occurred in the thorax.
2018-09-20 | GSE87058 | GEO
Project description:Comparison between groups of monozygotic (MZ) and dizygotic (DZ) twins enables an estimation of the relative contribution of genetic, shared and non-shared environmental factors to phenotypic variability. Using DNA methylation profiling of ~20,000 CpG sites as a phenotype, we have examined discordance levels in multiple tissues in neonatal twins. MZ twins exhibit a wide range of within-pair differences at birth, but show discordance levels generally lower than DZ pairs. Within-pair methylation discordance was lowest in CpG islands in all twins and increased as a function of distance from islands. This was largely independent of distance from transcriptional start site in promoters without CpG islands. Variance component decomposition analysis of DNA methylation in MZ and DZ pairs revealed a low mean heritability across all tissues, although a wide range of heritabilities was detected for specific genomic CpG sites. The largest component of variation was attributed to the combined effects of non-shared intrauterine environment and stochastic factors. Regression analysis of methylation on birth weight revealed a general association between methylation of genes involved in metabolism and biosynthesis, providing further support for epigenetic change in the previously described link between low birth weight and increasing risk for cardiovascular, metabolic and other complex diseases. Finally, comparison of our data with that of several older twins, revealed little evidence for genome-wide epigenetic drift with increasing age. This is the first study to analyse DNA methylation on a genome scale in twins at birth, further highlighting the importance of the intrauterine environment on shaping the neonatal epigenome.
2012-07-18 | GSE36642 | GEO
Project description:Follicular lymphoma is the most common indolent non-Hodgkin's lymphoma involving germinal centre B cells, with a subset of patients undergoing transformation to a diffuse large B-cell lymphoma (DLBCL) morphology for which the clinical outcomes are poor. To elucidate the differences in copy number profiles between FL and tFL groups, we performed Affymetrix SNP 6.0 Array analysis on 31 paired FL-tFL cases. We wanted to identify and compare recurrent somatic copy number alterations (CNAs) between the two groups (FL vs. tFL). In addition, the concordance and discordance in the copy neutral loss of heterozygosity (cnLOH) between the two groups were also investigated to identify recurrent target gene regions.
2013-10-01 | GSE42525 | GEO
Project description:<p>This study compares DNA mutations detected in matched primary and metastatic colorectal cancer samples from 18 individuals across 1,321 genes. We found many more mutations were shared between tumor pairs (avg. 33.3 mutations/tumor) than were discordant (avg. 2.3 mutations / tumor). Nearly all tumors showed at least one discordance, and these were observed in genes known to be involved in colorectal cancer progression. Therefore, although primary and metastatic colorectal tumors are highly genetically concordant, evidence exists for discordance, which has clinical implications especially in situations of chemotherapy resistance or insensitivity.</p>
| phs001084 | dbGaP