Effect of growth hormone gene polymorphism on growth traits in migratory Gaddi goats of Western Himalayas, India.

Abstract

Goat production under migratory system is foremost meat resource in Western Himalayan region of India. Thus, selection of goats for superior growth rate is rewarding. Growth hormone (GH) gene is identified as main regulator of post-natal growth and development. The objective of this study was to identify GH gene variants in Gaddi goats reared under migratory system via polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and single-strand conformation polymorphism (SSCP). Blood samples from 63 animals from different migratory flocks registered under All India Coordinated Research Project, Himachal Pradesh Agricultural University (HPAU), Palampur, were subjected to DNA isolation. A total of 422, 116, 389 and 181-bp amplicons were generated on amplification of four targeted regions of GH gene. GH1 and GH2 fragments were analysed using PCR-RFLP (HaeIII RE) that revealed three variants (AA, AB and BB) for GH1 having frequency as 0.27, 0.52 and 0.31, respectively whereas, two variants (AB and BB) were revealed for GH2 fragment having frequency of 0.24 and 076, respectively. GH3 and GH4 fragments were subjected to PCR-SSCP that detected three genotypes (AB, BB and AA) for GH3 with respective genotype frequency as 0.57, 0.21 and 0.22 respectively; however, GH4 was found to be monomorphic. The polymorphism information content values for GH1, GH2 and GH3 were 0.37, 0.36 and 0.34, respectively, which suggested the median level of polymorphism at studied loci and also indicated the effectiveness of the studied marker for population genetic studies. Significant associations (P ≤ 0.05) were detected for GH1 with 9-month body weight, GH2 with 9 and 12-month heart girth and GH3 with 6-month body weight, body height and body length, respectively. From the present study, it was concluded that SNPs and their association with some body measurements may be employed as useful markers for ongoing phenotypic selection programme.