Project description:This SuperSeries is composed of the following subset Series: GSE18642: Definitive SNP/CNV haplotype map of Asians determined using a collection of complete hydatidiform moles (Affymetrix) GSE18663: Definitive SNP/CNV haplotype map of Asians determined using a collection of complete hydatidiform moles (Illumina) Refer to individual Series
Project description:Only very few studies have investigated methylation patterns of different types of hydatidiform moles (HMs). Methylation patterns of androgenetic HMs (AnHMs) are abnormal due to the fact that the nuclear genome in AnHMs is inherited from the father, only. Diploid biparental HMs (BiHM) have been suggested to display the same methylation patterns of imprinted genes as AnHMs, and the methylation patterns are suspected to be a consequence of a failure to establish maternal methylation at multiple genome-wide loci. We have investigated the methylation patterns of AnHMs, BiHM-like placentas with a chr. 11p15.5 deletion and a BiHM from a woman with NLRP7 mutations and compared these to methylation patterns of normal placentas. Using the Next Generation Sequencing (NGS) technique Reduced Representation Bisulfite Sequencing (RRBS) we instigated the genome-wide CpG methylation of 32 samples, including nine normal placentas, 20 androgenetic diploid HMs (AnHMs), and three diploid biparental HMs/HM-like placentas. This dataset contains RRBS data from 12 samples, including the nine normal placentas and the three diploid biparental HMs/HM-like placentas.The RRBS data from 20 androgenetic diploid HMs (AnHMs) was deposited in GSE65881:http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE65881
Project description:Copy number variations (CNVs) are abundant, possibly variable among populations, and can confer various phenotypic variations such as risk to complex disease. We determined a genome-wide high resolution SNP/CNV haplotype structure of Asians, by analyzing a collection of complete hydatidiform moles (CHMs) of Japanese, using high-density DNA arrays. CHMs are tissues carrying duplicated haploid genomes that originated from single sperm, and have advantages as materials over conventional diploid cells in detecting CNVs by hybridization, because greater S/N ratios are expected, and overlapping CNV segments are independently detected without being bothered by possible heterozygous situations. Overall occupancy of CNV segments per haploid found here was at a level similar to previous reports. Approximately a half of our polymorphic CNV regions have not been described in the previous report for Asians, but the frequencies of most of these new CNV regions were low. The limited number of examined samples is likely to be the reason that they have escaped detection in the previous report. Many common CNV regions are resolvable to clusters of CNV segmets (that is, CNV events) on the basis of mutual overlap of the segments. The similarity of haplotype backgrounds surrounding different CNV events within the same CNV regions suggests that ancestral recurrences of CNV events were predominantly haplotype preferential. Illumina Human1M-Duov3 BeadChip analyses were performed according to the manufacturer's directions on DNA extracted from 5 complete hydatidiform moles (CHMs) tissues collected throughout Japan.
Project description:We analyzed high-dimensional RNA data to characterize molecular features of complete hydatidiform moles (CHMs) and corresponding pathologic pathways. CHMs and first trimester placentas were collected, histopathologically examined, then flash-frozen. Frozen CHMs and control placentas were subjected to RNA-Seq, with resulting data and published placental RNA-Seq data subjected to bioinformatics analyses. Of the 14,022 protein-coding genes expressed in all samples, 3729 were differentially expressed (DE) in CHMs of which 72% were up-regulated. DE genes were enriched in placenta-specific genes (OR = 1.88, p = 0.0001) of which 79% were down-regulated, imprinted genes (OR = 2.38, p = 1.54 × 10−6), and immune genes (OR = 1.82, p = 7.34 × 10−18), of which 73% were up-regulated. DNA methylation enzymes and histone demethylases were dysregulated. “Cytokine–cytokine receptor interaction” was the most impacted of 38 dysregulated pathways, among which 17 were immune-related pathways.
Project description:Mutations in components of the subcortical maternal complex (SMC) of the human oocyte are enigmatically associated with DNA methylation abnormalities specifically at imprinted genes in conceptuses, but the developmental timing, genomic extent and mechanistic details of these defects are unknown. Here, we show, by single-cell bisulphite sequencing, that mutation in human KHDC3L that causes recurrent hydatidiform mole results in a genome-wide deficit of de novo methylation in oocytes.
Project description:The haplotype map constructed by the International HapMap Project is a valuable source for the studies of disease genes, population structure, and evolution. In the Project, haplotypes have been inferred from experimentally determined genotypes, and are fairly accurate for Caucasians and Africans since the inference was based on the genotypes of trios. However, the inference for the Asians populations was less accurate, because of the lack of familial information. Here we assessed how the error in the inference can affect downstream studies, especially the analysis of recent positive selections, by comparing the results of the analyses using the data of HapMap JPT and of definitive haplotypes (DHaplo-DB) determined by us from a collection of Japanese complete hydatidiform moles (CHM), each of which carries a genome derived from a single sperm. We found that the error in JPT was not uniform throughout the genome, and the statistics for recent positive selection was significantly affected. Keywords: Definitive haplotype determination using CHMs, which carry haploid genomes. 100 CHM samples collected throughout Japan were analyzed by Affymetrix Genechip Mapping 500K Set array.
Project description:Genomic imprinting is a form of epigenetic regulation that results in expression of either the maternally or paternally inherited allele of a subset of genes. Imprinted loci contain differentially methylated regions (DMRs) where cytosine methylation marks one of the parental alleles, providing cis-acting regulatory elements that influence the allelic expression of surrounding genes, however to date the total number of imprinted loci within the human genome is unknown. To characterize known imprinted DMRS and identify novel imprinted loci we have performed whole-genome bisulphite sequencing and high-resolution DNA methylation array analysis of healthy tissues. Sequencing of bisulfite converted DNA and array based analysis of normal tissues, human embryonic stem cells, androgenetic hydatidiform moles and leukocytes from reciprocal genome-wide uniparental disomies.
Project description:The haplotype map constructed by the International HapMap Project is a valuable source for the studies of disease genes, population structure, and evolution. In the Project, haplotypes have been inferred from experimentally determined genotypes, and are fairly accurate for Caucasians and Africans since the inference was based on the genotypes of trios. However, the inference for the Asians populations was less accurate, because of the lack of familial information. Here we assessed how the error in the inference can affect downstream studies, especially the analysis of recent positive selections, by comparing the results of the analyses using the data of HapMap JPT and of definitive haplotypes (DHaplo-DB) determined by us from a collection of Japanese complete hydatidiform moles (CHM), each of which carries a genome derived from a single sperm. We found that the error in JPT was not uniform throughout the genome, and the statistics for recent positive selection was significantly affected. Keywords: Definitive haplotype determination using CHMs, which carry haploid genomes.
Project description:Maternal-effect mutations in components of the subcortical maternal complex (SCMC) of the human oocyte can cause early embryonic failure, gestational abnormalities and recurrent pregnancy loss. Enigmatically, they are also associated with DNA methylation abnormalities at imprinted genes in conceptuses, in the devastating gestational abnormality biparental complete hydatidiform mole (BiCHM) or in multi-locus imprinting disease (MLID). However, the developmental timing, genomic extent and mechanistic basis of these imprinting defects are unknown. Here, we studied methylation level of a women reported with familial recurrent hydatidiform mole and multiple pregnancy loss. Genotype analysis revealed homozygous mutation in KHDC3L. We obtained biparental mole from patient (Patient D) and compared it’s whole-genome methylation profile with respect to control placentas and sporadic mole (AnCHM) using Infinium MethylationEPIC BeadChip (WG-317-1001, Illumina). We also used endometrium samples from their respective mother for the comparison purposes. Molar conceptuses were observed with methylation defects at genome-wide level and profound loss of methylation at multiple genome-derived differentially methylated regions (gDMRs) confirming MLID.