Polymorphism of growth hormone gene in three goat breeds in Egypt

In Egypt, like other developing countries, goats are prime resources of meat. So, selection of goats for superior growth rate is advantageous. Growth hormone (GH) is the main regulator of animal growth, and encoded by GH gene that exhibits active gene variants improving growth. The objective of this study was to identify GH gene variants in three goat breeds (Barki, Damascus, and Zaraibi), via polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and gene sequencing analyses. Three loci on GH gene named GH1 , GH2 , and GH6 polymorphisms were analyzed. GH1 - Hae III/RFLP showed only two genotypes (AB and BB) in all breeds, with absent AA genotype. Both Barki and Zaraibi exhibited the highest GC genotype frequency (0.95). GH2 - Hae III/RFLP produced only two homozygous genotypes AA in Damascus and BB in both Barki and Zaraibi, with the absence of AB genotype in the three breeds. However, digestion of GH6 by Hae III was monomorphic; it exhibited different single-nucleotide polymorphisms (SNPs), detected by DNA sequencing, among the studied goat breeds. The revealed SNPs could be employed as useful markers, helping goat breeders in selection of goats for high growth performance. Further analyses with larger sample size are needed for investigating the relationship between the different genotypes and growth traits.