title: A comprehensive survey of copy number variation in 18 diverse pig populations and identification of candidate copy number variable genes associated with complex traits.
abstract: BACKGROUND
  Copy number variation (CNV) is a major source of structural variants and has been commonly identified in mammalian genome. It is associated with gene expression and may present a major genetic component of phenotypic diversity. Unlike many other mammalian genomes where CNVs have been well annotated, studies of porcine CNV in diverse breeds are still limited.
  
  
  RESULTS
  Here we used Porcine SNP60 BeadChip and PennCNV algorithm to identify 1,315 putative CNVs belonging to 565 CNV regions (CNVRs) in 1,693 pigs from 18 diverse populations. Total 538 out of 683 CNVs identified in a White Duroc × Erhualian F2 population fit Mendelian transmission and 6 out of 7 randomly selected CNVRs were confirmed by quantitative real time PCR. CNVRs were non-randomly distributed in the pig genome. Several CNV hotspots were found on pig chromosomes 6, 11, 13, 14 and 17. CNV numbers differ greatly among different pig populations. The Duroc pigs were identified to have the most number of CNVs per individual. Among 1,765 transcripts located within the CNVRs, 634 genes have been reported to be copy number variable genes in the human genome. By integrating analysis of QTL mapping, CNVRs and the description of phenotypes in knockout mice, we identified 7 copy number variable genes as candidate genes for phenotypes related to carcass length, backfat thickness, abdominal fat weight, length of scapular, intermuscle fat content of logissimus muscle, body weight at 240 day, glycolytic potential of logissimus muscle, mean corpuscular hemoglobin, mean corpuscular volume and humerus diameter.
  
  
  CONCLUSIONS
  We revealed the distribution of the unprecedented number of 565 CNVRs in pig genome and investigated copy number variable genes as the possible candidate genes for phenotypic traits. These findings give novel insights into porcine CNVs and provide resources to facilitate the identification of trait-related CNVs.
authors.affiliation: Key Laboratory for Animal Biotechnology of Jiangxi Province and the Ministry of Agriculture of China, Jiangxi Agricultural University, Nanchang, 330045, China.
authors.forename: Congying
authors.initials: C
authors.lastname: Chen
authors.forename: Ruimin
authors.initials: R
authors.lastname: Qiao
authors.forename: Rongxing
authors.initials: R
authors.lastname: Wei
authors.forename: Yuanmei
authors.initials: Y
authors.lastname: Guo
authors.forename: Huashui
authors.initials: H
authors.lastname: Ai
authors.forename: Junwu
authors.initials: J
authors.lastname: Ma
authors.forename: Jun
authors.initials: J
authors.lastname: Ren
authors.forename: Lusheng
authors.initials: L
authors.lastname: Huang
mesh_terms: D000818:Animals; D001823:Body Composition / Q000235:genetics; D049628:Body Size / Q000235:genetics; D001947:Breeding / Q000379:methods*; D002681:China; D056915:DNA Copy Number Variations / Q000235:genetics*; D056726:Genetic Association Studies; D005828:Genetics, Population; D005838:Genotype; D016014:Linear Models; D051379:Mice; D018345:Mice, Knockout; D058977:Molecular Sequence Annotation; D010641:Phenotype; D040641:Quantitative Trait Loci / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D013045:Species Specificity; D013552:Swine / Q000235:genetics*