Project description:The little skate, a cartilaginous fish evolutionarily distal from tetrapods, displays walking-like behavior and has conserved genetic programs and neuronal substrates for land-walking. Studies on little skate have been limited due to lack of high-quality genome assembly. Here, we generated an improved genome assembly of little skate reflecting precise gene annotation and structures and performed integrated analysis of gene expression and chromatin accessibility to investigate molecular mechanisms of fin motor neuron development. Through interspecies comparison of RNA expression, common and species-specific genes expressed in fin/limb/wing level motor neurons were identified. Moreover, by performing chromatin accessibility analysis with a pure fin motor neuron population the potential regulators controlling the gene expression in fin motor neurons were identified. Interspecies comparison of genomic data, gene expression, and chromatin accessibility assay suggest that the little skate has highly conserved gene regulatory mechanisms controlling tetrapod locomotion, which was not previously expected.
Project description:The little skate, a cartilaginous fish evolutionarily distal from tetrapods, displays walking-like behavior and has conserved genetic programs and neuronal substrates for land-walking. Studies on little skate have been limited due to lack of high-quality genome assembly. Here, we generated an improved genome assembly of little skate reflecting precise gene annotation and structures and performed integrated analysis of gene expression and chromatin accessibility to investigate molecular mechanisms of fin motor neuron development. Through interspecies comparison of RNA expression, common and species-specific genes expressed in fin/limb/wing level motor neurons were identified. Moreover, by performing chromatin accessibility analysis with a pure fin motor neuron population the potential regulators controlling the gene expression in fin motor neurons were identified. Interspecies comparison of genomic data, gene expression, and chromatin accessibility assay suggest that the little skate has highly conserved gene regulatory mechanisms controlling tetrapod locomotion, which was not previously expected.
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:The 9p21.3 cardiovascular disease locus is the most influential common genetic risk factor for coronary artery disease, accounting for ~10-15% of disease among non-African populations. The ~60kb risk haplotype is human-specific and lacks coding genes, hindering efforts to decipher its function. Genetic studies implicate the 9p21.3 locus and other risk genes to effects in the vascular wall. Here, we use genome editing to delete the entire risk on non-risk haplotype from the genomes of human iPSCs and perform genomewide transcriptional profiling along the timecourse of their differentiation into vascular smooth muscle cells (VSMCs). These studies identify a network of ~3000 genes governed by the risk haplotype in VSMCs that predict deficits in cell division, adhesion and contraction, which we confirmufunctionally. Remarkably, deleting the risk haplotype reverts VSMCs to resemble the non-risk VSMCs, suggesting that the risk region drives a cell state transition. transcriptionally and functionally. . Deleting the risk haplotype reverts these cells to reverted to the non-risk of iPSCs we show that the non-risk haplotype has little effect on locus we produce iPSCs from risk and non-risk individuals, delete each haplotype using genome editing and generate vascular smooth muscle cells (VSMCs). We show that risk VSMCs exhibit aberrant adhesion and contraction, concomitant with dramatically altered global transcriptional changes that are enriched in previously identified cardiovascular disease genes and pathways. Unexpectedly, deleting the risk haplotype rescues VSMC transcriptional identity and function, while expressing the 9p21.3-associated long non-coding RNA ANRIL induces risk phenotypes in non-risk VSMCs. This studies shows that the risk haplotype dominantly predisposes VSMCs to adopt perturbed phenotypes associated with cardiovascular disease and establishes haplotype-edited iPSCs as powerful tools for functionally annotating human-specific variation in non-coding genomic regions.