Project description:Allelic differences between the two sets of chromosomes can affect the propensity of inheritance in humans, but the extent of such differences in the human genome has yet to be fully explored. Here, we delineate allelic chromatin modifications and transcriptomes amongst a broad set of human tissues, enabled by a chromosome-span haplotype reconstruction strategy1. The resulting haplotype-resolved epigenomic maps reveal extensive allele bias in the transcription of human genes as well as chromatin state, allowing us to infer cis-regulatory relationships between genes and their control sequences. These maps also uncover a new class of cis regulatory elements and detail activities of repetitive elements in various human tissues. The rich datasets described here will enhance our understanding of the mechanisms controlling tissue-specific gene expression programs. One replicate of Hi-C experiment in four human tissues with four different individuals (Thymus STL001, Aorta STL002, Leftventricle STL003, and Liver STL011).
Project description:Constructing high-quality haplotype-resolved genome assemblies has substantially improved the ability to detect and characterize genetic variants. A targeted approach providing readily access to the rich information from haplotype-resolved genome assemblies will be appealing to groups of basic researchers and medical scientists focused on specific genomic regions. Here, using the 4.5 megabase, notoriously difficult-to-assemble major histocompatibility complex (MHC) region as an example, we demonstrated an approach to construct haplotype-resolved assembly of the targeted genomic region with the CRISPR-based enrichment. Compared to the results from haplotype-resolved genome assembly, our targeted approach achieved comparable completeness and accuracy with reduced computing complexity, sequencing cost, as well as the amount of starting materials. Moreover, using the targeted assembled personal MHC haplotypes as the reference both improves the quantification accuracy for sequencing data and enables allele-specific functional genomics analyses of the MHC region. Given its highly efficient use of resources, our approach can greatly facilitate population genetic studies of targeted regions, and may pave a new way to elucidate the molecular mechanisms in disease etiology.
Project description:Constructing high-quality haplotype-resolved genome assemblies has substantially improved the ability to detect and characterize genetic variants. A targeted approach providing readily access to the rich information from haplotype-resolved genome assemblies will be appealing to groups of basic researchers and medical scientists focused on specific genomic regions. Here, using the 4.5 megabase, notoriously difficult-to-assemble major histocompatibility complex (MHC) region as an example, we demonstrated an approach to construct haplotype-resolved assembly of the targeted genomic region with the CRISPR-based enrichment. Compared to the results from haplotype-resolved genome assembly, our targeted approach achieved comparable completeness and accuracy with reduced computing complexity, sequencing cost, as well as the amount of starting materials. Moreover, using the targeted assembled personal MHC haplotypes as the reference both improves the quantification accuracy for sequencing data and enables allele-specific functional genomics analyses of the MHC region. Given its highly efficient use of resources, our approach can greatly facilitate population genetic studies of targeted regions, and may pave a new way to elucidate the molecular mechanisms in disease etiology.
Project description:Allelic differences between the two sets of chromosomes can affect the propensity of inheritance in humans, but the extent of such differences in the human genome has yet to be fully explored. Here, we delineate allelic chromatin modifications and transcriptomes amongst a broad set of human tissues, enabled by a chromosome-span haplotype reconstruction strategy1. The resulting haplotype-resolved epigenomic maps reveal extensive allele bias in the transcription of human genes as well as chromatin state, allowing us to infer cis-regulatory relationships between genes and their control sequences. These maps also uncover a new class of cis regulatory elements and detail activities of repetitive elements in various human tissues. The rich datasets described here will enhance our understanding of the mechanisms controlling tissue-specific gene expression programs.
Project description:Analysis of genotypes at 150,000 SNPs reveals patterns of allele and haplotype sharing that describes the breed relationships and development of 161 breeds of dog.
Project description:Allergy to hazelnut seeds ranks among the most prevalent food allergies in Europe. The aim of this study was to elucidate the gastrointestinal digestion of hazelnut allergens on molecular level. Hazelnut flour was digested in vitro following the Infogest consensus model. For six allergenic proteins, the time-dependent course of digestion was monitored by SDS-PAGE and HPLC−MS/MS, and degradation products were characterized by a bottom-up proteomics approach. Depending on the molecular structure, a specific biochemical fate was observed for each allergen, and degradation kinetics were traced back to the peptide level. 1183 peptides were characterized, including 130 peptides that carry known IgE-binding epitopes and may represent sensitizers for hazelnut allergy. The kinetics of peptide formation and degradation were determined by label free quantification and follow a complex multi-stage mechanism.
Project description:Constitutional epimutations of tumor suppressor genes manifest as promoter methylation and transcriptional silencing of a single allele in normal somatic tissues, thereby predisposing to cancer. Constitutional MLH1 epimutations occur in individuals with young-onset cancer and demonstrate non-Mendelian inheritance through their reversal in the germline. We report a cancer-affected family showing dominant transmission of soma-wide highly mosaic MLH1 methylation and transcriptional repression linked to a particular genetic haplotype. The epimutation was erased in spermatozoa but reinstated in the somatic cells of the next generation. The affected haplotype harbored two single nucleotide substitutions in tandem: c.-27C>A located near the transcription initiation site and c.85G>T. The c.-27C>A variant significantly reduced transcriptional activity in reporter assays and is the probable cause of this epimutation.
Project description:Trans-homolog interactions encompass potent regulatory functions, which have been studied extensively in Drosophila, where homologs are paired in somatic cells and pairing-dependent gene regulation, or transvection, is well-documented. Nevertheless, the structure of pairing and whether its functional impact is genome-wide have eluded analysis. Accordingly, we generated a diploid cell line from divergent parents and applied haplotype-resolved Hi-C, discovering that homologs pair relatively precisely genome-wide in addition to establishing trans-homolog domains and compartments. We also elucidated the structure of pairing with unprecedented detail, documenting significant variation across the genome. In particular, we characterized two forms: tight pairing, consisting of contiguous small domains, and loose pairing, consisting of single larger domains. Strikingly, active genomic regions (A-type compartments, active chromatin, expressed genes) correlated with tight pairing, suggesting that pairing has a functional role genome-wide. Finally, using RNAi and haplotype-resolved Hi-C, we show that disruption of pairing-promoting factors results in global changes in pairing.