Aassociation of growth hormone promoter region with twining rate in Markhoz breed goats

This study was conducted in order to investigate polymorphism of the growth hormone gene and its relationship with twining trait in 150 individuals from Markhoz breed goats of Iran. In sequencing process of PCR products, a SNP C>A in the promoter of growth hormone gene was observed at 87 nucleotide of the fragment amplified. The frequency of 0.72 and 0.28 were obtained for CC and CA genotypes, respectively. Shannon’s information index (I) was estimated equal to 0.40 and it indicated high genetic diversity in promoter of growth hormone gene for this population. The Chi-square statistics (3.86) showed Hardy-Weinberg disequilibrium in the population (P<0.05). Odds ratios (ORs) statistics for twinning trait was estimated 1.12 (P>0.05) and 5.14 (P<0.1) in the first parity compared to the second and third parity, respectively and as well as 5.81 (P<0.05) in the second parity compared to the third parity. Therefore, the results obtained for twining rate in different parities showed a superiority for twining rate as parity 1> parity 2> parity3. The Chi-square (0.04) and as well as OR (1.035) statistics demonstrated non-significant differences between two CC and CA genotypes of growth hormone gene promoter for twining rate (P>0.05). Based on the results, it can be suggested to investigate other polymorphisms in growth hormone gene or candidate genes for twining rate in order to improve twining rate in Markhoz goats.