Project description:We used a Drosophila melanogaster line (a "double balancer") carrying balancer chromosomes for both the second (CyO) and third (TM3) chromosomes. We crossed the double balancer to an isogenic wild-type "virginizer" line to obtain trans-heterozygous adults from the F1 generation. Whole-genome sequencing and mate pair sequencing were used to identify Single Nucleotide Variants (SNVs) and Structural Variants (SVs) on both chromosomes.
Project description:Copy number variants (CNVs) are a major source of genetic variation in human health and disease. Previous studies have suggested replication stress, such as that caused by the polymerase inhibitor aphidicolin, as a causative factor in CNV formation, but existing data are technically limited in the quality of the comparisons which can be made to experimentally induced variants. Here we used 1M feature single-nucleotide polymorphism (SNP) arrays and mate-pair sequencing as high resolution methods for characterizing CNVs in a common set of samples, to compare both the properties of constitutional and induced CNVs as well as the utility of the two methods in an experimental setting. Although the optimized methods provided complementary information, sequencing was more sensitive to small variants and provided superior structural descriptions that allowed some CNVs to be associated with inversions, ectopic duplications or LINE insertions. The majority of constitutional and all aphidicolin-induced CNVs appear to be formed via homology-independent mechanisms, while aphidicolin-induced CNVs were of a larger median size than constitutional events even when mate-pair data were considered. Aphidicolin thus appears to stimulate formation of CNVs that closely resemble human pathogenic CNVs and the subset of larger nonhomologous constitutional CNVs. One untreated and one aphidicolin-treated subclone of human fibroblast cell line HGMDFN090 were analyzed by Illumina HumanOmni1-Quad SNP array and low-density mate-pair sequencing.
Project description:The draft genome of L. sativa (lettuce) cv. Tizian was sequenced in two Illumina sequencing runs, mate pair and shotgun. This entry contains the RAW sequencing data.
Project description:Copy number variants (CNVs) are a major source of genetic variation in human health and disease. Previous studies have suggested replication stress, such as that caused by the polymerase inhibitor aphidicolin, as a causative factor in CNV formation, but existing data are technically limited in the quality of the comparisons which can be made to experimentally induced variants. Here we used 1M feature single-nucleotide polymorphism (SNP) arrays and mate-pair sequencing as high resolution methods for characterizing CNVs in a common set of samples, to compare both the properties of constitutional and induced CNVs as well as the utility of the two methods in an experimental setting. Although the optimized methods provided complementary information, sequencing was more sensitive to small variants and provided superior structural descriptions that allowed some CNVs to be associated with inversions, ectopic duplications or LINE insertions. The majority of constitutional and all aphidicolin-induced CNVs appear to be formed via homology-independent mechanisms, while aphidicolin-induced CNVs were of a larger median size than constitutional events even when mate-pair data were considered. Aphidicolin thus appears to stimulate formation of CNVs that closely resemble human pathogenic CNVs and the subset of larger nonhomologous constitutional CNVs.
Project description:<p>Recently developed methods that utilize partitioning of long genomic DNA fragments, and barcoding of shorter fragments derived from them, have succeeded in retaining long-range information in short sequencing reads. These so-called read cloud approaches represent a powerful, accurate, and cost-effective alternative to single-molecule long-read sequencing. We developed software, GROC-SVs, that takes advantage of read clouds for structural variant detection and assembly. We apply the method to two 10x Genomics data sets, one chromothriptic sarcoma with several spatially separated samples, and one breast cancer cell line, all Illumina-sequenced to high coverage. Comparison to short-fragment data from the same samples, and validation by mate-pair data from a subset of the sarcoma samples, demonstrate substantial improvement in specificity of breakpoint detection compared to short-fragment sequencing, at comparable sensitivity, and vice versa. The embedded long-range information also facilitates sequence assembly of a large fraction of the breakpoints; importantly, consecutive breakpoints that are closer than the average length of the input DNA molecules can be assembled together and their order and arrangement reconstructed, with some events exhibiting remarkable complexity. These features facilitated an analysis of the structural evolution of the sarcoma. In the chromothripsis, rearrangements occurred before copy number amplifications, and using the phylogenetic tree built from point mutation data, we show that single nucleotide variants and structural variants are not correlated. We predict significant future advances in structural variant science using 10x data analyzed with GROC-SVs and other read cloud-specific methods.</p>
Project description:We identified genomic structural alterations of six patients with signs of neurodevelopmental disorder (NDDs) that harbour chromosomal rearrangements using large-insert paired-end tag sequencing (DNA-PET). This technique allowed the refinement of chromosomal breakpoints and lead to the identification of seven disrupted genes (GNAQ, RBFOX3, UNC5D, TMEM47, NCAPG2, GTDC1 and XIAP). For one patient we filtered the entire panel of structural variations (SVs) with his parents and identified a unique SV that disrupted a single gene: GTDC1. We then validated the functional consequences of the chromosomal breakpoint disruption of GTDC1 by using patient-derived iPSCs. By differentiating these cells into neural progenitor cells (NPCs) and neurons, we interrogated the disease process at the cellular level and observed defects in the proliferation and glycosylation status of NPCs and also defects in neuronal maturation and function. We compared these results with GTDC1-deficient wild-type human NPCs and neurons, and observed similar phenotypic features as in the patient-derived cells which confirm that GTDC1 is involved in the patient’s phenotype. We show here that the combination of genomic screening with iPSCs technology provides a mechanistic insight into possible contributory effects of candidate genes implicated in NDDs and for personalized medicine. Structural variations were identified by long insert DNA paired-end tag (DNA-PET) sequencing, a mate-pair sequencing approach.