Growth hormone gene polymorphism in domestic and wild goat breeds in Kurdistan region of Iraq using PCR-RFLP and SNP markers

Abstract

In Iraq generally and Kurdistan region especially, goats are an important resource for meat and milk production. It is well known that growth hormone (GH) is involved in a variety of biological activities in livestock animals, including reproduction, growth, lactation, metabolism etc. The goal of this research was to reveal the polymorphism of GH gene in different Capra hircus breeds (native, Shami, Meriz and Kamori goat) and in wild mountain goat (Capra aegagrus) via PCR-RFLP technique and direct seqencing. GH1 (exon 2 and 3) and GH2 (exon 4) polymorphisms on the GH gene were investigated. In all breeds, GH1-Hae III/RFLP revealed only two genotypes (homozygous AA and heterozygous AB), with absent genotype BB. The genotype frequency was 0.886 for the AB genotype and 0.114 for the AA genotype; the allelic frequency was 0.558 for the A allele and 0.442 for the B allele. The average of observed heterozygosity was 0.882 and observed homozygosity was 0.118, indicating that the GH1 was polymorphic. The sequence data of GH1 gene of Meriz and wild goats revealed a SNP at the position 58 (C to T) of the wild goat that has led to a change in amino acid proline to serine. GH2 digestion by Hae III, on the other hand, was monomorphic with the CC homozygous genotype. The results of PCR-RFLP and SNP experiments from this investigation were evaluated as very useful in genotype analysis of local goat breeds/populations. Thus, DNA polymorphisms in the growth hormone gene could be used as reliable genetic markers in breeding programmes in this region.