Novel SNP detection in GH and GHR genes and its potential influence on growth traits in Anatolian Southern Yellow cattle.

The growth hormone (GH) and its receptor (GHR) are crucial regulators of growth traits in cattle. In this study, we identified two novel single SNPs in the GH and GHR genes of Anatolian Southern Yellow cattle and evaluated their association with key growth parameters. The first SNP, c.491 C > G, was identified in exon 2 of the GH gene, resulting in a missense mutation that substitutes leucine with valine. Similarly, the second SNP, c.173425 A > T, was detected in exon 9 of the GHR gene as a synonymous mutation that did not alter the amino acid sequence. Genotype and allele frequency analysis revealed that the GH locus exhibited a distribution of CC (0.67) and GG (0.33) with corresponding allele frequencies of C (0.67) and G (0.33). In contrast, the GHR locus exhibited AA (0.80) and TT (0.20) genotypes, with allele frequencies of A (0.80) and T (0.20), indicating conformity to the Hardy-Weinberg equilibrium. Association analysis demonstrated that the GH c.491 C > G SNP was significantly associated with increased body weight and higher body length (p < 0.05). Additionally, the GHR c.173425 A > T SNP was significantly associated with greater chest girth (p < 0.05). These results suggest that genetic variation in the GH and GHR genes may influence growth performance in Anatolian Southern Yellow cattle, highlighting their potential as candidate markers for marker-assisted selection.