Genome Detection Of Copy Number Variations Among Diverse Horse Breeds By Array CGH

Recent research have found that copy number variation (CNV) is widespread in human or animal genomes and is a significant source of genetic variation, and which have been shown to be associated with phenotypic diversity. However, CNV research about horse genome is rarely reported compared with other livestock.CNVs in6different breeds of mare horses (Mongolia horse, Abaga horse, Hequ horse, Kazakh horse, Debao pony and Thoroughbred) were identified using aCGH. In total, seven hundred CNVs were identified ranging in size from6.1Kb to0.57Mb across all autosomes. Through merging overlapping CNVs, we found a total of353CNV regions (CNVRs). The length of the CNVRs ranged from6.1Kb to1.45Mb with average and median sizes of38.49Kb and13.1Kb. These CNVRs spaned13.59Mb and accounted for approximately0.61%of the horse genome sequence.518annotated genes were affected by CNVs, which correspond to about2.26%of all the horse genes.Through the gene ontology (GO), genetic pathway analysis and comparison of CNV genes among different breeds, we found that7CNVs genes may be related to the adaptation to plateau severe environment of these plateau horses. To confirm these findings, five CNVRs identified by aCGH were validated using quantitative PCR (qPCR), and found89.69%of the qPCR results were consistent with the aCGH chip. ConclusionsThis study was the first report of copy number variations in Chinese horses, which indicated that CNVs were ubiquitous in the horse genome and regulated a variety of biological processes, and this research was significant to study the molecular mechanism of adaptation to plateau severe environment of horses.