Identification of copy number variants in whole-genome data using Reference Coverage Profiles.

TitleIdentification of copy number variants in whole-genome data using Reference Coverage Profiles.
Publication TypeJournal Article
Year of Publication2015
AuthorsGlusman G, Severson A, Dhankani V, Robinson M, Farrah T, Mauldin DE, Stittrich AB, Ament SA, Roach JC, Brunkow ME, Bodian DL, Vockley JG, Shmulevich I, Niederhuber JE, Hood L
JournalFront Genet
Volume6
Pagination45
Date Published2015
Abstract<p>The identification of DNA copy numbers from short-read sequencing data remains a challenge for both technical and algorithmic reasons. The raw data for these analyses are measured in tens to hundreds of gigabytes per genome; transmitting, storing, and analyzing such large files is cumbersome, particularly for methods that analyze several samples simultaneously. We developed a very efficient representation of depth of coverage (150-1000× compression) that enables such analyses. Current methods for analyzing variants in whole-genome sequencing (WGS) data frequently miss copy number variants (CNVs), particularly hemizygous deletions in the 1-100 kb range. To fill this gap, we developed a method to identify CNVs in individual genomes, based on comparison to joint profiles pre-computed from a large set of genomes. We analyzed depth of coverage in over 6000 high quality (>40×) genomes. The depth of coverage has strong sequence-specific fluctuations only partially explained by global parameters like %GC. To account for these fluctuations, we constructed multi-genome profiles representing the observed or inferred diploid depth of coverage at each position along the genome. These Reference Coverage Profiles (RCPs) take into account the diverse technologies and pipeline versions used. Normalization of the scaled coverage to the RCP followed by hidden Markov model (HMM) segmentation enables efficient detection of CNVs and large deletions in individual genomes. Use of pre-computed multi-genome coverage profiles improves our ability to analyze each individual genome. We make available RCPs and tools for performing these analyses on personal genomes. We expect the increased sensitivity and specificity for individual genome analysis to be critical for achieving clinical-grade genome interpretation.</p>
DOI10.3389/fgene.2015.00045
Alternate JournalFront Genet
PubMed ID25741365
PubMed Central IDPMC4330915
Grant ListP50 GM076547 / GM / NIGMS NIH HHS / United States