Assessment of polymorphisms in mysostatin gene and their allele substitution effects showed weak association with growth traits in Iranian Markhoz goats

SUMMARY Polymorphisms in the myostatin (MSTN) gene were detected in 150 female Iranian Markhoz goats. Two 573 base pairs (bp) and 475 bp fragments of the MSTN gene, which contains a deletion 5 bp indel (206 TTTTA/), in the region of exon 1 encoding the 5′ untranslated region (UTR) of the MSTN transcript, and two single-nucleotide polymorphisms (SNPs) of substitution (339T/A, 169T/G) in exon 1 and 3 regions, respectively, were amplified. The polymerase chain reaction (PCR) products were digested separately using restriction enzyme endonuclease DraI, HinIII and HindIII. The digestion results indicated AA and AB genotypes in the region of exon 1 encoding the 5′UTR of the MSTN transcript, AA, AT and TT genotypes in exon 1 and TT, TG and GG genotypes in exon 3. The SNPs loci were in Hardy–Weinberg disequilibrium but the deletion locus showed equilibrium in the Markhoz goat population. Evaluation of associations between the polymorphisms with the studied growth traits showed that the AA and GG genotypes of exons 1 and 3 have a significant positive effect on weight at 6 months of age (W6) and average daily gain (ADG) traits, but genotypes in the region of exon 1 encoding the 5′UTR of the MSTN transcript did not have any significant effect on the studied growth traits. The statistical analyses showed a positive and significant effect of the 339A allele (exon 1) for W6 and negative and significant effect of the 169G allele (exon 3) for ADG trait. Therefore, these results suggest that the MSTN gene could be a potential candidate gene that affects ADG and W6 traits in goats. More studies are needed to simultaneously consider variants of this region in a larger population to better understand MSTN gene effects on the economic traits in goat.