Single nucleotide polymorphism (SNP) in growth hormone gene of Jakhrana, a prominent milk goat breed in India

PCR-SSCP patterns on non-degenerative PAGE revealed 6 amplicons in caprine GH exon-4 and 3 alleles A4, B4 and C4 were identified. In exon-5, six SSCP variants revealed three alleles A5, B5, and C5. Out of 54 AA sites of GH-4 coding region, six codons were polymorphic. At codon-6, nucleotide substitution of G/A resulted in to genotypes 6RR, 6HH and G/C into genotypes 6PP, 6RP. At codon-36, A/G nucleotide substitution resulted in to newer genotypes 36GG from that of 36DD in reference Genbank sample. At codon-54, C/T nucleotide substitution caused change of amino acid (AA) from arginine (R) to tryptophan (W) resulted into a new genotype of 54WW in comparison to 54RR of Genbank reference sample. In exon-5, out of 67 AA sites 8 codons were polymorphic, but the codons 14 and 60 were preponderant. At codon-14, A/G substitution resulted into 3 genotypes 14KK, 14EE and 14KE with frequency of 0.52, 0.38 and 0.10, respectively. At codon-60, G/C and G/A substitutions resulted in to 3 genotypes 60GG, 60RR and 60GR with frequencies of 0.48, 0.42 and 0.10, respectively. Synonymous mutations as compared to Genbank accession D00476.1 were present at codons 25, 31 and 62 in all the animals of Jakhrana goats. The high genetic variability in GH gene exon-4 and exon-5 may be useful in exploring their associations with milk and growth traits in goat for further genetic improvement.