Sequencing of growth hormone gene for detection of polymorphisms and their relationship with body weight in Harri sheep

This study aimed to evaluate the relationship between growth hormone (GH) gene polymorphism and estimated body weight in Harri sheep. One hundred Harri sheep lambs were used to determine the birth weight (BW) and weight at 120 days of age. The daily live-weight gain (DLWG) 0-120 days (g) was calculated. The complete CDS of the Harri sheep GH gene is 2117pb in length (GenBank acc. no. KU255857). Three novel SNPs were detected by comparing with GenBanke acc. no. X12546_1. The G871A SNP in intron II, G1383A in exon IV that resulted in conversion of the amino acid arginine number 121 to lysine (R121K) and the A1509G in intron IV. Each SNP was found on both alleles the mutant homozygote was more common (48, 56 and 50%) than the heterozygote (30, 18 and 20%) for G871A, G1383A and A1509G respectively. A positive significant (P<0.05) correlation between growth traits (BW, 120 day body weight and DLWG) and SNP and a highly significant correlation with the genotype were detected. The regression analysis indicated the positive effect of genotype and SNPs on the growth traits. Individuals carrying homozygote mutant alleles had the heaviest body weight and the highest DLWG. Consequently, these SNP may be useful indicators in the selection of lambs for higher growth rate and meat production.