Association analysis of aquaporin 7 (AQP7) gene variants with semen quality and fertility in bulls
Aquaporin 7 (AQP7) gene as a candidate Antifreeze gene was investigated and associated with fresh and frozen semen quality traits in 45 Simmental and Charolais bulls. PCR-SSCP, PCR-RFLP, and sequencing method were employed to detect the single nucleotide polymorphisms (SNPs) of the AQP7 gene. Two mutations, A264G and G371C, were identified. The allele frequencies were A (0.97, 0.96) to B (0.03, 0.04) and C (0.97, 0.91) to D (0.03, 0.09) in Simmental and Charolais bulls, respectively. A264G substitution was significantly associated with acrosome integrity ratio (P < 0.01) and motility (P < 0.05) in frozen semen. Meanwhile, G371C substitution was significantly associated with acrosome integrity ratio (P < 0.05), percentages of viable sperm (P < 0.05), and motility (P < 0.01) in frozen semen. The results prove that AQP7 gene SNPs are useful for marker-assisted selection in early seed selection in the bull industry.
Key words: AQP7 gene, single nucleotide polymorphisms, SNPs, association analysis, Simmental bulls, Charolais bulls