Polymorphisms of PPARGC1A gene and their association with milk production traits in Holstein cows.
The PPARGC1A gene was studied as a candidate gene for the five milk production traits(milk yield at 305 d,protein percentage,fat percentage,lactose percentage and dry matter percentage) in Holstein cows.According to the sequence of bovine PPARGC1A gene,eighteen pairs of primers were designed to detect polymorphisms of PPARGC1A gene in 435 Holstein cows by PCR-RFLP,PCR-PAGE and PCR-SSCP.The results showed that only the products amplified by primers P1,P2,P16 and P18 displayed polymorphisms.For P1,three genotypes(CC,CT and TT) were detected in Holstein cows by digesting the PCR products with restriction endonuclease HaeⅢ.Least squares mean of fat percentage for TT or CT was significantly higher than that for CC(P0.05),the difference of the least squares mean for fat percentage was not significant between TT and CT(P0.05).For P2,three genotypes(AA,AC and CC) were detected in Holstein cows by digesting the PCR products with restriction endonuclease NheⅠ.Least squares mean of protein percentage for AA or AC was significantly higher than that for CC(P0.05),the difference of the least squares mean for protein percentage was not significant between AA and AC(P0.05).For P16,three genotypes(EE,EF and FF) were detected in Holstein cows.The differences of the least squares means for the five milk production traits between EE,EF and FF were not significant(P0.05).For P18,three genotypes(GG,GH and HH) were detected in Holstein cows.The differences of the least squares means for the five milk production traits between GG,GH and HH were not significant(P0.05).The results preliminarily indicated that allele T of C85330T polymorphic site of PPARGC1A gene is a potential DNA marker for improving fat percentage in dairy cattle,and allele A of A103592C polymorphic site of PPARGC1A gene is a potential DNA marker for improving protein percentage in dairy cattle.