Project description:We present a computational tool, FounderTracker, for discovering founder mutations in cancer, based on the detection of significantly conserved haplotypes in tumor SNP profiles. We demonstrate the relevance of the approach by identifying founder mutations in two different cancers, and we show with simulated data that FounderTracker can detect rare founder mutations with high power and negligible false discovery rate. FounderTracker is a powerful tool for discovering novel founder mutations that may explain part of the "missing" heritability in cancer. This SuperSeries is composed of the SubSeries listed below.
Project description:Sole ulcers (SU) and white line disease (WLD) are noninfectious claw lesions that arise due to compromised horn production and are common causes of lameness in dairy cattle, imposing welfare and profitability concerns. The low to moderate heritability estimates of SU and WLD susceptibility indicate that genetic selection could reduce their prevalence. To identify loci associated with SU and WLD susceptibility, generalized linear mixed model (GLMM) regression and random forest (RF) genome-wide association studies (GWAS) were performed. Cows from five commercial dairies in California were classified as sound controls having no instances of lameness and above six years of age (n = 102) or cases having SU (n = 152), WLD (n = 117), SU and/or WLD (SU+WLD, n = 198), or any type of noninfectious claw lesion (n = 217). Top SNPs were defined as those passing Bonferroni-corrected suggestive and significance thresholds in the GLMM analysis or those that a validated RF model considered important. Effects of top SNPs were quantified using Bayesian estimation. Linkage disequilibrium (LD) blocks defined by top SNPs were explored for candidate genes and previously identified, functionally relevant quantitative trait loci. The GLMM GWAS revealed regions of association on BTA8 for SU and BTA13 common to WLD, SU+WLD, and noninfectious claw lesions. Bayesian estimation of effect sizes indicated that these SNPs had effects significantly different from zero, indicating their small but notable contribution to susceptibility. Promising candidate genes identified in these regions were involved in wound healing, skin lesions, bone growth and mineralization, adipose tissue, and keratinization. The LD block defined by the most significant SNP on BTA8 for SU included a SNP previously reported to be associated with SU. The RF models were overfitted, indicating that SNP effects were very small and thereby preventing meaningful interpretation of SNPs with the highest importance values and downstream analyses. These findings suggested that variants associated with a variety of physiological systems may contribute to susceptibility for noninfectious claw lesions, demonstrating the complexity of genetic predisposition.
Project description:A large number of sequence variants have been linked to complex human traits and diseases, but deciphering their biological functions is still challenging since most of them reside in the noncoding DNA. To fill this gap, we have systematically assessed the binding of 270 human transcription factors (TF) to 95,886 noncoding variants in the human genome using an ultra-high-throughput multiplex protein-DNA binding assay, termed SNP evaluation by Systematic Evolution of Ligands by EXponential enrichment (SNP-SELEX). The resulting 828 million measurements of TF-DNA interactions enable estimation of the relative affinity of these TFs to each variant in vitro and allow for evaluation of the current methods to predict the impact of noncoding variants on TF binding. We show that the Position Weight Matrices (PWMs) of most TFs lack sufficient predictive power, while the Support Vector Machine (SVM) combined with the gapped k-mer representation show much improved performance, when assessed on results from independent SNP-SELEX experiments involving a new set of 61,020 sequence variants. We report highly predictive models for 94 human TFs and demonstrate their utility in genome-wide association studies (GWAS) and understanding of the molecular pathways involved in diverse human traits and diseases.
Project description:Contour integration is a key function of the visual system to deal with occlusion and discontinuity in natural scenes. The current study is the first one to investigate the genetic basis of this visual function in humans. A total of 2619 normal participants were tested on their ability to detect continuous contours embedded in a cluttered background with a standard psychophysical protocol. Multi-level genomic analysis was performed, involving heritability estimation based on single nucleotide polymorphism (SNP) and association testing at SNP and gene levels.
Project description:Comparison of SNP profiles of the Patagonain Sheepdog with European breeds confirms Scottish origin and position basal to modern herding breeds.
Project description:CRISPR-based epigenome editing was recently used to activate gene expression through direct transcriptional activation or site-specific DNA demethylation. Viral delivery of guide RNAs for these purposes remains to be developed. Furthermore, currently available viral delivery tools for genome editing show meager rates of heritability. Here, we have developed a tobacco rattle virus (TRV)-based guide RNA delivery system for both transcriptional activation and targeted DNA demethylation. To promote heritable epigenome editing specifically within plant meristems and the germline, we used the tRNA-guide RNA expression system to express guide RNAs from the viral genome, thus facilitating cell-to-cell movement of the RNA in plants. We achieved up to ~8% heritability of the induced phenotype in the progeny of virus-inoculated plants and 25% in the following generation, indicating high rates of heritability for targeted DNA demethylation. Thus, TRV delivery, in combination with a specific tRNA-gRNA architecture, provides for fast and effective epigenome editing.