MyoD基因在不同猪种中的PCR-RFLP遗传多态性及其遗传效应研究

PCR-RFLP Polymorphisms and Genetic Effects of MyoD Gene in Different Pig Breeds

采用PCR-RFLP的方法分析了MyoD基因在10个中外猪种及部分杂交群体中的分布情况,并分析了MyoD基因对肌纤维、胴体品质、胴体等级性状和肉质性状的遗传效应。结果表明:MyoD基因内含子1内的DdeⅠ酶切位点多态性较丰富。在多数地方猪种群体中,C基因的分布具有绝对优势,且主要以杂合子AC形式存在。突变型A基因对胴体性状和胴体等级性状的影响较大,可极显著地增加胴体瘦肉率和眼肌面积,降低皮脂含量,提高腿臀比例,增加胴体长度(P<0.01),同时会降低猪肉品质。具体讲,A基因对增加肌纤维面积的加性效应值和显性效应值分别为457.915μm2和431.055μm2;对增加胴体瘦肉率的加性效应值和显性效应值分别为3.594%和-0.153%;对增加眼肌面积的加性效应值和显性效应值分别为3.084cm2和-0.46cm2;对皮脂率的加性效应值和显性效应值分别为-3.916%和0.666%;对提高腿臀比的加性效应值为0.771%,显性效应值为0.068%。A基因对屠宰后45min和冷藏24h后的肉色评分的加性效应值分别为-0.145和-0.160,显性效应值分别为-0.052和-0.213。

PCR-RFLP technique was applied in this study to analyze the distribution of MyoD genotypes in 10 different pig breeds and pig breed crosses. The genetic effects of MyoD gene on muscle fiber, carcass quality, carcass grading traits and meat quality traits were analyzed. The results indicated that the MyoD/Dole I polymorphisms detected in the intron 1 of the gene were abundant in these testing pig breed groups. The C allele was more frequent in most Chinese native pig breeds and mainly existed in the form of AC heterozygotes. The mutation allele A had significant positive effects on most of carcass quality traits and carcass grading traits, but had negative effects on most of meat quality traits. The A allele can highly significantly increase the carcass lean percent, loin eye area, ham percent and carcass length, and decrease fat content （P〈0.01）. The A allele had additive effects of increasing 457. 915 μm^2 of the size of muscle fiber, 3. 594% of the carcass lean percent, 3. 084 cm^2 of the loin eye area, -3. 915 5% of the carcass fat content, 0. 771% of the ham percent, -0. 145 and -0. 160 of the meat color score tested by color plate at 45 minutes and 24 hours after slaughtered. The A allele had dominant effects of increasing 431. 055 μm^2 of thesize of muscle fiber, -0. 153% of the carcass lean percent, -0.46 cm^2 of loin eye area, 0. 666% of the carcass fat content, 0. 068% of the ham percent, -0. 052 and -0. 213 of the meat color score tested by color plate at 45 minutes and 24 hours after slaughter respectively.