Identification of point mutation in  GH and CAST genes and their association with growth traits of sheep

Sunil  Kumar

Identification of point mutation in GH and CAST genes and their association with growth traits of sheep

Date

2022-09

Authors

Sunil Kumar

Publisher

Lala lajpat rai university Hisar

Abstract

The present study was carried out on 184 sheep (138 Harnali and 46 Munjal) maintained in the Department of Animal Genetics and Breeding, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana to study the polymorphism in GH and CAST genes and its association with performance and body conformation traits. One set of primers each for targeted regions of GH and CAST gene was used. The PCR product of 422 bp size of the GH gene was amplified encompassing exon 2 and 3 in Harnali and Munjal sheep. The PCR product was digested with HaeIII restriction enzyme for detection of SNP. The digested products revealed presence of two genotypes i.e. AA and AB in the studied population. Candidate A>G mutation (A781G) was observed in our targeted sheep population. AA genotype was found to be the predominant genotype in both Harnali (0.62) and Munjal (0.96). Chi square value revealed that Harnali sheep population with respect to target locus was not under Hardy-Weinberg equilibrium. Exon and intron regions from a portion of the first repetitive domain of the CAST gene were amplified to a product of 622 bp and after digestion with Msp1 revealed monomorphic pattern in both Harnali and Munjal sheep. Period of birth was found to have significant effect on W-WT, 9M-WT and Y WT, BL, BH and PG in Harnali sheep and on 9M-WT, AGFW, HG and PG in Munjal sheep. Sex of lamb was found to have significant (P<0.05) effect on W-WT and highly significant (P<0.01) effect on 6M-WT, 9M-WT, Y-WT and AGFW in Harnali sheep. Sex of lamb showed highly significant (P<0.01) effect on 6M-WT, 9M-WT and Y-WT Munjal too. In Harnali sheep, Dam’s weight at lambing had highly significant (P<0.01) influence on all performance traits viz., B-WT, W-WT, 6M-WT, 9M-WT, Y-WT and AGFW and significant effect on BL and HG. In Munjal, Dam’s weight at lambing was having positive but non significant influence on all the performance traits. The breeding values of growth traits ranging -2.494 to 1.912 kg and -2.999 to 4.447 kg in Harnali and Munjal sheep, respectively indicated variability between the genetic worth of different individuals for growth traits. Effect of genotype was found to be significant (P<0.05) on annual grease fleece weight. AB genotype animals had significantly higher AGFW than those having AA genotype. AB genotype was found to be associated with higher annual grease fleece weight and can be used as potential candidate marker in selection criteria for improving grease fleece weight in Harnali sheep