PCR-SSCP Variation of GH and STAT5A Genes and Their Association with Estimated Breeding Values of Growth Traits in Baluchi Sheep

Abstract

Growth hormone (GH) selected for its important role in economically relevant traits and signal transducers and activators of transcription 5A (STAT5A) is also known as a main mediator of growth hormone action on target genes. A total number of 190 lambs of Iranian purebred Baluchi sheep were genotyped at exon 5 of GH and exons 7 and 8 of STAT5A genes by using PCR-SSCP analysis. GH gene revealed three (G1, G2, and G3) conformational patterns; however, STAT5A loci were not polymorphic. Breeding values of growth traits including birth weight, weaning weight, 6 months weight, 9 months weight, and yearling weight were estimated by using the Best Linear Unbiased Prediction based on an animal model with a relationship matrix. Studied growth traits were examined for association analysis. Our findings suggest that animals with G2 genotype have highest breeding value for six month weight, while these animals have lowest breeding value for pre-weaning traits. Higher performance of G2 animals in adult ages may be related to the growth hormone role in puberty ages. The other traits showed no relationship to the genotypes examined.