Novel copy number variation of the KLF3 gene is associated with growth traits in beef cattle.

Copy number variation (CNV) related to complex traits, such as disease and quantitative phenotype, is considered an important and wealthy source of genetic and phenotypic diversity. It suggests that the copy number variation of function gene maybe leads to the phenotypic changes. Kupple like factor 3 (KLF3) gene is a vital transcription factor associated with the growth and development of muscle and adipose tissue. It has been mapped in a CNV region by animal genome re-sequencing. In this study, we detected the distribution diversity of KLF3 gene copy numbers in six Chinese cattle breeds (QC, NY, XN, PN, QDM and JX) and associated the phenotypic traits with it. Then, we analyzed the KLF3 gene transcription expression level in different tissues of Jiaxian (JX) cattle. Furthermore, we detected mRNA expression level of muscle and fat tissues of Jiaxian cattle (JX), Angus × Jiaxian (AJ). The results showed that the copy number in CNV loss was more frequent in QC than others. And we revealed a positive effect of KLF3 CNV on growth traits, such as body mass and heart girth (P < 0.05). In a word, we ascertained the significance between CNVs of KLF3 gene and growth traits in different cattle breeds, and our data indicates that the CNVs of KLF3 gene may as a marker for the future molecular breeding of Chinese beef cattle.