Allelic and genotypic frequencies in polymorphic Booroola fecundity gene and their association with multiple birth and postnatal growth in Chhotanagpuri sheep

Abstract

Aim: Chhotanagpuri breed of sheep reared for mutton in Jharkhand, India, having problem of low litter size and bodyweight. The response of genetic improvement for traits with low heritability through traditional selection method is timeconsuming.Therefore, marker-assisted selection based on a polymorphism study of suitable candidate gene can responsequickly. Thus, this study was aimed at identification of different allelic and genotypic frequencies of Booroola fecundity(FecB) gene and its association with multiple birth and postnatal growth in Chhotanagpuri sheep.Materials and Methods: DNA isolation and gene-specific amplification of FecB gene was performed from blood samplesof from 92 Chhotanagpuri lambs maintained under similar feeding and management conditions. Custom nucleotidesequencing and single-strand conformational polymorphism analysis were performed to identify different genotypes withrespect to the target gene. Statistical analysis was performed for determination of allelic and genotypic frequencies of FecBgene polymorphisms and its association with multiple birth and postnatal growth of lambs from birth to 52 weeks age.Results: "AA" "AB" and "BB" genotypes were found at locus-1 as it is polymorphic for FecB gene while locus-2 wasfound to be monomorphic for FecB gene. Higher frequency of "A" allele at locus-1 was found in single born lambs, whereas"B" allele was predominant among multiple born lambs. The lambs having "BB" genotype weighed significantly (p≥0.01)heavier than those of "AB" and "AA" genotype at 52 weeks of age.Conclusion: "BB" genotype has emerged as favored genotype for multiple births and better growth indicator. Therefore,homozygous lambs for "B" allele should be selected and utilized in breeding program for better growth rate.