Analysis of the correlations between growth hormone receptor gene polymorphism and body size indexes in cattle

Abstract

Polymorphism in exon 10 of growth hormone receptor (GHR) was detected in three cattle breeds (Nanyang cattle, limousin and galloway), They were at A/T at nt. 495, C/T at nt. 622, A/C at nt. 650, T/C at nt. 702 and A/G at nt. 730. Results indicated that there were six genotypes, namely AA, BB, CC, AB, AC and BC. The frequencies of different genotypes in different breeds and the relationship between the six genotypes and traits of these cattle were analyzed using a linear model. Statistical results showed that the GHR SSCP sites in Nanyang, Limousin and Galloway cattle were at Hardy-Weinberg Equilibrium. The polymorphism information content (PIC) values indicated that the SSCPs were highly polymorphic (PIC < 0.50) in the Nanyang breed, and were moderately polymorphic in Limousin and Galloway breeds. The least squares means of body weight of 12-month-old cattle was lower for genotype CC than for genotypes AB and BC (P<0.05, P<0.01, respectively). The least squares means of body weight of 18-month-old cattle was lower for genotype CC than for BC (P < 0.05). The least squares means of heart girth in 18-month-old cattle was lower for genotype CC than for AB (P < 0.05). There was no difference in the genotype distribution among other genotypes.