Project description:Genome-wide association studies (GWAS) have been highly informative in discovering disease-associated loci, but are not designed to capture all structural variations in the human genome. Using long-read sequencing data, we discovered widespread structural variation within SVA (Sine-VNTR-Alu) elements, a class of great-ape specific transposable elements with gene-regulatory roles, which represents a major source of structural variability in the human population. We highlight the presence of structurally variable SVAs (SV-SVAs) in neurological disease-associated loci, and further associate SV-SVAs to disease-associated SNPs and differential gene expression using luciferase assays and expression quantitative trait loci data. Finally, we genetically deleted SV-SVAs in the BIN1 and CD2AP Alzheimer-associated risk loci and in the BCKDK Parkinson disease-associated risk locus and assessed multiple aspects of their gene-regulatory influence in a human neuronal context. Together, this study reveals a novel layer of genetic variation in transposable elements that may contribute to identification of the structural variants that are the actual drivers of disease-associations of GWAS loci.
Project description:Phenotypic variation is essential for the selection of new traits of interest. Structural variants, consisting of deletions, duplications, inversions, and translocations, have greater potential for phenotypic consequences than single nucleotide variants. Indeed, pan-genome studies have highlighted the importance of structural variation in the evolution and selection of novel traits. Here, we describe a simple method to induce structural variation in plants. We demonstrate that a short period of growth on the topoisomerase II inhibitor etoposide induces heritable structural variation and altered phenotypes in Arabidopsis thaliana at high frequency. Using long-read sequencing and genetic analysis, we identified causative deletions and inversions underlying semi-dominant and recessive phenotypes. This method is potentially applicable to any plant species, with minimal resources required, and is suitable to replace irradiation as a source of induced large-effect structural variation.
Project description:Phenotypic variation is essential for the selection of new traits of interest. Structural variants, consisting of deletions, duplications, inversions, and translocations, have greater potential for phenotypic consequences than single nucleotide variants. Indeed, pan-genome studies have highlighted the importance of structural variation in the evolution and selection of novel traits. Here, we describe a simple method to induce structural variation in plants. We demonstrate that a short period of growth on the topoisomerase II inhibitor etoposide induces heritable structural variation and altered phenotypes in Arabidopsis thaliana at high frequency. Using long-read sequencing and genetic analysis, we identified causative deletions and inversions underlying semi-dominant and recessive phenotypes. This method is potentially applicable to any plant species, with minimal resources required, and is suitable to replace irradiation as a source of induced large-effect structural variation.
Project description:Phenotypic variation is essential for the selection of new traits of interest. Structural variants, consisting of deletions, duplications, inversions, and translocations, have greater potential for phenotypic consequences than single nucleotide variants. Indeed, pan-genome studies have highlighted the importance of structural variation in the evolution and selection of novel traits. Here, we describe a simple method to induce structural variation in plants. We demonstrate that a short period of growth on the topoisomerase II inhibitor etoposide induces heritable structural variation and altered phenotypes in Arabidopsis thaliana at high frequency. Using long-read sequencing and genetic analysis, we identified causative deletions and inversions underlying semi-dominant and recessive phenotypes. This method is potentially applicable to any plant species, with minimal resources required, and is suitable to replace irradiation as a source of induced large-effect structural variation.
Project description:DNA structural variation (SV) comprises a major portion of genetic diversity, but its biological impact is unclear. We propose that the genetic history and extraordinary phenotypic variation of dogs make them an ideal mammal in which to study the effects of SV on biology and disease. The hundreds of existing dog breeds were created by selection of extreme morphological and behavioral traits. And along with those traits, each breed carries increased risk for different diseases. We used array CGH to create the first map of DNA copy number variation (CNV) or SV in dogs. The extent of this variation, and some of the gene classes affected, are similar to those of mice and humans. Most canine CNVs affect genes, including disease and candidate disease genes, and are thus likely to be functional. We identified many CNVs that may be breed or breed class specific. Cluster analysis of CNV regions showed that dog breeds tend to group according to breed classes. Our combined findings suggest many CNVs are (1) in linkage disequilibrium with flanking sequence, and (2) associated with breed specific traits. We discuss how a catalog of structural variation in dogs will accelerate the identification of the genetic basis of canine traits and diseases, beginning with the use of whole genome association and candidate CNV/gene approaches. Chen WK, Swartz JD, Rush LJ, Alvarez, CE. Mapping DNA structural variation in dogs. Genome Res. 2009. 19: 500 509 PMID: 19015322 Array comparitive genomic hybridization analysis of structural variation in 9 dogs, and 1 lymphoma cell line.