Project description:A CNV map in pigs could facilitate the identification of chromosomal regions that segregate for important economic and disease phenotypes. The goal of this study was to identify CNV regions (CNVRs) in pigs based on a custom array comparative genome hybridization (aCGH). We carried out a custom-made array comparative genome hybridization (aCGH) experiment in order to identify copy number variations (CNVs) in the pig genome analysing animals of diverse pig breeds (White Duroc, Yangxin, Erhualian, Tongcheng, Large White, Pietrain, Landrace and Chinese new pig line DIV ) using a tiling oligonucleotide array with ~720,000 probes designed on the pig genome (Sus scrofa genome version 9.0).
Project description:Structural and functional impacts of copy number variations (CNVs) on livestock genomes are not yet well understood. In this study, we have identified 1853 CNV regions (CNVRs) using population-scale sequencing data generated from 75 cattle of 8 breeds (Holstein, Angus, Jersey, Limousin, Romagnola, Brahman, Gir and Nelore). Individual genome sequence coverage ranged from 4 to 30 fold, with a mean of 11.8 fold. A total of 3.1% (87.5 Mb) of the cattle genome is predicted to be copy number variable, representing a substantial increase over the previous estimates (~2%). This dataset was highly correlated with array CGH data (r2 = 0.761) and was validated to be accurate with an estimated 12% false positive rate and a 19% false negative rate based on qPCR and array CGH, respectively. Hundreds of CNVs were found to be either breed specific or differentially variable across breeds, including the RICTOR gene in dairy breeds and the PNPLA3 gene in the beef breeds. In contrast, clusters of the PRP and PAG genes are duplicated in all sequenced animals, implicating that subfunctionalization, neofunctionalization or overdominance play a role in diversifying these fertility related genes. Further population-genetic analyses based on CNVs revealed the population structures of these taurine and indicine breeds and uncovered hundreds of positively selected CNV candidates near important functional genes. These CNV results provide a new glimpse of diverse selections during cattle speciation, domestication, breed formation, and recent genetic improvement.