Polymorphisms of the CAPN, CAST, LEP, GH, GHR, IGF-1 and MSTN loci of Colombian Creole hair x Pelibuey sheep sheep crossbreeds

Abstract

The objective of this study was to characterize single nucleotide polymorphisms at the Calpain (CAPN), Calpastatin (CAST), Leptin (LEP), Growth Hormone (GH), Growth Hormone Receptor (GHR), Insulin-Like Growth Factor 1 (IGF-1) and myostatin (MSTN) loci in Columbian Creole hair sheep crossed with Pelibuey sheep. In 192 individuals, the CAST and MSTN loci were genotyped by PCR-RFLP, and the CAPN, GH, GHR, IGF-1 and LEP loci by PCR-SSCP and sequences. The following parameters were calculated: allelic and genotypic frequencies, observed (Ho) and expected (He) heterozygosity, fixation index and deviations from Hardy-Weinberg equilibrium (HWE). In the CAPN locus, higher frequencies of the T allele (70%) were found with respect to C (30%) and the frequencies of the TT (46%) and TC (48%) genotypes exceeded the CC (6%) genotype. For the CAST locus, the MM genotype (83%) was the most frequent, followed by the other genotypes (MN 16% and NN 0.5%) and thus the allelic frequencies were M: 91% and N: 9%. The allele A (66%) of the LEP locus was more frequent than the G allele (34%) and the AA, AG and GG genotypes had frequencies of 43, 47 and 10%, respectively. Only two genotypes (AA 64% and AG 36%) were found in the GH locus with allelic frequencies of 82 and 18% for A and G respectively. In the locus IGF-1, the genotypes AA, GG, and AG presented frequencies of 36, 49 and 15%, respectively, with a greater presence of the G allele (56%) than A (44%). In the analysed population, the GHR and MSTN loci were monomorphic, and only the AA and MM genotypes were found in each. The CAST, GH, and IGF-1 loci showed deviations from HWE. He deficit was found only in the IGF-1 locus. The CAPN, CAST, LEP, GH, and IGF-1 loci were polymorphic with high He and excess heterozygotes, in contrast, the GHR and MST loci were monomorphic. The data presented here could be used in animal breeding programmes.