Single nucleotide polymorphisms in ghrelin gene and the resulting genetic variants at ghrelin locus in different strains of indigenous Tswana chickens

Abstract

Ghrelin is a growth hormone releasing peptide which also affects feed intake in chickens. Ghrelin is encoded by chicken ghrelin gene (cGHRL) found in chromosome 7. Single nucleotide polymorphisms (SNPs) have been reported in cGHRL in Chinese native chickens, but such studies have not been carried out in chickens native to Africa. The aim of this study was therefore to identify SNPs in cGHRL in three strains of indigenous Tswana chickens. DNA was isolated from the blood of 60 indigenous Tswana chickens and three pairs of primers were used for amplification of cGHRL. The resultant plymerase chain reaction (PCR) products were sent to Inqaba Biotec (Pretoria, South Africa) for DNA sequencing. A total of 25 SNPs were found in cGHRL gene in different strains of Tswana chickens. Fourteen of the SNPs have been previously reported and the rest are novel SNPs, which might be unique to Tswana chickens. Two non-synonymous SNPs (A429G and A2355G) were found in the coding region of cGHRL gene in the normal strain and only the A2355G SNP was found in dwarf and naked neck strains. The SNPs in the coding region resulted in three alleles in the normal strains and two alleles in the dwarf and naked neck strains.

Keywords: Single nucleotide polymorphisms (SNPs), ghrelin gene, Tswana chickens