Copy number variation of bovine MAPK10 modulates the transcriptional activity and affects growth traits

Beef production is an economically important sector of animal husbandry and much attention has been paid on the identification of molecular markers associated with gene expressions and growth traits. The aim of this study was to search for potential effects of a novel copy number variation (CNV) located in intron 10 of bovine Mitogen-Activated Protein Kinase 10 (MAPK10) on phenotypic variation. Cattle of nine Chinese domestic breeds were included: Qinchuan (QC), Nanyang (NY), Xianan (XN), Jiaxian (JX), Jinnan (JN), Qinghai (QH), Dzomo (DZ), Fu (FU) and Chinese Holstein cattle (CH). In total, genomic DNA of 455 female cattle and RNA of 27 fetal and/or adult tissues of QC cattle were used. Methods of Real-time quantitative PCR, Pearson Product Moment Correlation and ANOVA were applied to evaluate the copy number distributions and their effects on genes' transcriptional levels and growth traits. Substantial genetic differences between NY cattle and other four breeds (XN, QH, DZ and FU) were observed (P < 0.05 or P < 0.01). Negative correlations between copy numbers and transcript levels of MAPK10 /MYOG were shown in fetal skeletal muscle (P < 0.01). Statistical analysis between CNV and growth traits revealed that the NY cattle with copy number gain type showed better traits, including body weight (P < 0.05), body height and chest girth (P < 0.01). These results suggested that this CNV locus could modulate the transcriptional activity and thereby affect the phenotypic traits. Our study firstly indicated that the CNV at MAPK10 locus was a promising genetic marker to improve meat production in beef cattle breeding.