Abstract: In this study, the relationship of MyoD gene polymorphisms and meat yield was studied by molecular biology methods. The aim was to provide scientific basis for improving meat performance of Altay sheep by molecular marker assisted breeding methods. One year old ram of Altay (n=120) were chosen in representative area to jugular vein blood, MyoD gene 5' control region and the part of the exon 1 pieces were selected to detect genetic polymorphism by PCR-SSCP, and the effects on weight traits were analyzed. It was used to research the relationship between MyoD genetic polymorphisms and meat performance. There was no polymorphism in MyoD-P1 gene locus (5' flanking region );There was polymorphism in MyoD-P2 gene locus (326-542 bp in exon 1), the primer MyoD-P2 gene locus existence three kinds of genotypes of AA, AB and BB. Sequencing results showed that there was a base mutation A→G in location 408 bp in MyoD gene exon 1. The mutation causesd its coding changing from histidine into alanine. By correlation analysis it was found that the individual weight of AA genotype were much higher than BB genotype (P<0.05). Mutational site exon 1 of MyoD gene might be the important site of Altay sheep's meat performance, MyoD gene might be the candidate genes of Altay sheep's meat performance.

Key words: Altay sheep; MyoD gene; meat yield