scholarly journals SVScore: An Impact Prediction Tool For Structural Variation

2016 ◽  
Author(s):  
Liron Ganel ◽  
Haley J Abel ◽  
Ira M Hall

Motivation: Structural variation (SV) is an important and diverse source of human genome variation. Over the past several years, much progress has been made in the area of SV detection, but predict-ing the functional impact of SVs discovered in whole genome sequencing (WGS) studies remains extremely challenging. Accurate SV impact prediction is especially important for WGS-based rare variant association studies and studies of rare disease. Results: Here we present SVScore, a computational tool for in silico SV impact prediction. SVScore aggregates existing per-base single nucleotide polymorphism pathogenicity scores across relevant genomic intervals for each SV in a manner that considers variant type, gene features, and uncertainty in breakpoint location. We show that in a Finnish cohort, the allele frequency spectrum of SVs with high impact scores is strongly skewed toward lower frequencies, suggesting that these variants are under purifying selection. We further show that SVScore identifies deleterious variants more effectively than naive alternative methods. Finally, our results indicate that high-scoring tandem duplications may be under surprisingly strong selection relative to high-scoring deletions, suggesting that duplications may be more deleterious than previously thought. In conclusion, SVScore provides pathogenicity prediction for SVs that is both informative and meaningful for understanding their functional role in disease. Availability: SVScore is implemented in Perl and available freely at {{http://www.github.com/lganel/SVScore}} for use under the MIT license. Contact: [email protected]

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Joan P Breyer ◽  
Jeffrey R Smith

Abstract Genome-wide association studies bring into focus specific genetic variants of particular interest for which validation is often sought in large numbers of study subjects. Practical alternative methods are limiting for the application of genotyping few variants in many samples. A common scenario is the need to genotype a study population at a specific high-value single nucleotide polymorphism (SNP) or insertion-deletion (indel). Not all such variants, however, will be amenable to assay by a given approach. We have adapted a single-nucleotide primer extension (SNuPE) method that may be tailored to genotype a required variant, and implemented it as a useful general laboratory protocol. We demonstrate reliable application for production-scale genotyping, successfully converting 87% of SNPs and indels for assay with an estimated error rate of 0.003. Our implementation of the SNuPE genotyping assay is a viable addition to existing alternative methods; it is readily customizable, scalable, and uses standard reagents and a laboratory plate reader.


2019 ◽  
Vol 17 (06) ◽  
pp. 1940012
Author(s):  
Yuan Liu ◽  
Yongchao Ma ◽  
Evan Salsman ◽  
Frank A. Manthey ◽  
Elias M. Elias ◽  
...  

Mapping short reads to a reference genome is an essential step in many next-generation sequencing (NGS) analyses. In plants with large genomes, a large fraction of the reads can align to multiple locations of the genome with equally good alignment scores. How to map these ambiguous reads to the genome is a challenging problem with big impacts on the downstream analysis. Traditionally, the default method is to assign an ambiguous read randomly to one of the many potential locations. In this study, we explore two alternative methods that are based on the hypothesis that the possibility of an ambiguous read being generated by a location is proportional to the total number of reads produced by that location: (1) the enrichment method that assigns an ambiguous read to the location that has produced the most reads among all the potential locations, (2) the probability method that assigns an ambiguous read to a location based on a probability proportional to the number of reads the location produces. We systematically compared the performance of the proposed methods with that of the default random method. Our results showed that the enrichment method produced better results than the default random method and the probability method in the discovery of single nucleotide polymorphisms (SNPs). Not only did it produce more SNP markers, but it also produced SNP markers with better quality, which was demonstrated using multiple mainstay genomic analyses, including genome-wide association studies (GWAS), minor allele distribution, population structure, and genomic prediction.


2016 ◽  
Vol 283 (1835) ◽  
pp. 20160569 ◽  
Author(s):  
M. E. Goddard ◽  
K. E. Kemper ◽  
I. M. MacLeod ◽  
A. J. Chamberlain ◽  
B. J. Hayes

Complex or quantitative traits are important in medicine, agriculture and evolution, yet, until recently, few of the polymorphisms that cause variation in these traits were known. Genome-wide association studies (GWAS), based on the ability to assay thousands of single nucleotide polymorphisms (SNPs), have revolutionized our understanding of the genetics of complex traits. We advocate the analysis of GWAS data by a statistical method that fits all SNP effects simultaneously, assuming that these effects are drawn from a prior distribution. We illustrate how this method can be used to predict future phenotypes, to map and identify the causal mutations, and to study the genetic architecture of complex traits. The genetic architecture of complex traits is even more complex than previously thought: in almost every trait studied there are thousands of polymorphisms that explain genetic variation. Methods of predicting future phenotypes, collectively known as genomic selection or genomic prediction, have been widely adopted in livestock and crop breeding, leading to increased rates of genetic improvement.


2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Wim Gorssen ◽  
Roel Meyermans ◽  
Steven Janssens ◽  
Nadine Buys

Abstract Background Runs of homozygosity (ROH) have become the state-of-the-art method for analysis of inbreeding in animal populations. Moreover, ROH are suited to detect signatures of selection via ROH islands and are used in other applications, such as genomic prediction and genome-wide association studies (GWAS). Currently, a vast amount of single nucleotide polymorphism (SNP) data is available online, but most of these data have never been used for ROH analysis. Therefore, we performed a ROH analysis on large medium-density SNP datasets in eight animal species (cat, cattle, dog, goat, horse, pig, sheep and water buffalo; 442 different populations) and make these results publicly available. Results The results include an overview of ROH islands per population and a comparison of the incidence of these ROH islands among populations from the same species, which can assist researchers when studying other (livestock) populations or when looking for similar signatures of selection. We were able to confirm many known ROH islands, for example signatures of selection for the myostatin (MSTN) gene in sheep and horses. However, our results also included multiple other ROH islands, which are common to many populations and not identified to date (e.g. on chromosomes D4 and E2 in cats and on chromosome 6 in sheep). Conclusions We are confident that our repository of ROH islands is a valuable reference for future studies. The discovered ROH island regions represent a unique starting point for new studies or can be used as a reference for future studies. Furthermore, we encourage authors to add their population-specific ROH findings to our repository.


2010 ◽  
Vol 30 (6) ◽  
pp. 1411-1420 ◽  
Author(s):  
Jason B. Wright ◽  
Seth J. Brown ◽  
Michael D. Cole

ABSTRACT Genome-wide association studies have mapped many single-nucleotide polymorphisms (SNPs) that are linked to cancer risk, but the mechanism by which most SNPs promote cancer remains undefined. The rs6983267 SNP at 8q24 has been associated with many cancers, yet the SNP falls 335 kb from the nearest gene, c-MYC. We show that the beta-catenin-TCF4 transcription factor complex binds preferentially to the cancer risk-associated rs6983267(G) allele in colon cancer cells. We also show that the rs6983267 SNP has enhancer-related histone marks and can form a 335-kb chromatin loop to interact with the c-MYC promoter. Finally, we show that the SNP has no effect on the efficiency of chromatin looping to the c-MYC promoter but that the cancer risk-associated SNP enhances the expression of the linked c-MYC allele. Thus, cancer risk is a direct consequence of elevated c-MYC expression from increased distal enhancer activity and not from reorganization/creation of the large chromatin loop. The findings of these studies support a mechanism for intergenic SNPs that can promote cancer through the regulation of distal genes by utilizing preexisting large chromatin loops.


2021 ◽  
pp. 1-11
Author(s):  
Valentina Escott-Price ◽  
Karl Michael Schmidt

<b><i>Background:</i></b> Genome-wide association studies (GWAS) were successful in identifying SNPs showing association with disease, but their individual effect sizes are small and require large sample sizes to achieve statistical significance. Methods of post-GWAS analysis, including gene-based, gene-set and polygenic risk scores, combine the SNP effect sizes in an attempt to boost the power of the analyses. To avoid giving undue weight to SNPs in linkage disequilibrium (LD), the LD needs to be taken into account in these analyses. <b><i>Objectives:</i></b> We review methods that attempt to adjust the effect sizes (β<i>-</i>coefficients) of summary statistics, instead of simple LD pruning. <b><i>Methods:</i></b> We subject LD adjustment approaches to a mathematical analysis, recognising Tikhonov regularisation as a framework for comparison. <b><i>Results:</i></b> Observing the similarity of the processes involved with the more straightforward Tikhonov-regularised ordinary least squares estimate for multivariate regression coefficients, we note that current methods based on a Bayesian model for the effect sizes effectively provide an implicit choice of the regularisation parameter, which is convenient, but at the price of reduced transparency and, especially in smaller LD blocks, a risk of incomplete LD correction. <b><i>Conclusions:</i></b> There is no simple answer to the question which method is best, but where interpretability of the LD adjustment is essential, as in research aiming at identifying the genomic aetiology of disorders, our study suggests that a more direct choice of mild regularisation in the correction of effect sizes may be preferable.


2001 ◽  
Vol 6 (3) ◽  
pp. 18-30
Author(s):  
M M Chabeli

The recommendations made in the article on nurse educators’ perceptions of OSCE as a clinical evaluation method (Chabeli, 2001:84-91) are addressed in this article.OpsommingIn hierdie artikel word daar gefokus op die aanbevelings wat gedoen is met betrekking tot die persepsies van verpleeg- opvoedkundiges ten opsigte van die OGKE as ‘n kliniese evalueringsmetode (Chabeli, 2001:84-91). *Please note: This is a reduced version of the abstract. Please refer to PDF for full text.


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