Mutations in HSP70-2 gene change the susceptibility to clinical mastitis in Chinese Holstein

Abstract To select the molecular markers susceptible to mastitis and reduce the loss induced by mastitis, the PCR-SSCP method was adopted to investigate the correlation between SNPs of the HSP70-2 gene and mastitis in 103 Chinese Holstein. 25 new polymorphisms were detected in this study: 9 SNPs (g.− 115 G → A, g.− 98 T → C, g.117 C → A, g.156 A → C, g.1743 G → A, g.1746 C → T, g.1761 T → G, g.1770 C → G, g.1877 G → C) were found to be associated with mastitis; 2 key SNPs led to amino-acid changes: g.1770 C → G (590 Asp → Glu), g.1877 G → C (626 Gly → Ala). 626 Gly → Ala affected the protein secondary structure. 3 potential cow HSP70-2 proteins were found in all the 103 individuals, but predicted three-dimensional structures of 3 proteins are the same with each other. It is suggested that 9 SNPs increase the susceptibility to mastitis due to their low polymorphisms and can be used as molecular markers to breed the dairy cows resistant to mastitis.