中文摘要：

采用PCR-SSCP方法对莱芜猪、大蒲莲猪、沂蒙黑猪和里岔黑猪的肌细胞生成素（myogenin，MyoG）基因5’端进行单核苷酸多态性检测，并分析MyoG基因对猪的初生重、60日龄重、210日龄重，60-210日龄平均日增重和背膘厚的影响。根据猪MyoG基因5’端的DNA序列（U14331）设计3对引物，发现5-2引物对扩增的片段有多态性，且存在3种基因型（AA、AB、BB）。并对纯合子进行测序，发现2080位G→A突变。χ^2独立性检验表明，基因型频率在莱芜猪和犬蒲莲猪与沂蒙黑猪和里岔黑猪间存在显著差异（P〈0．05）。固定效应模型分析结果表明，初生重基因型间差异显著（P〈0．05），而60日龄重、210日龄重、60-210日龄平均日增重和背膘厚基因型间差异不显著（P〉0．05）。最小二乘分析结果表明，BB基因型与其他两种基因型比较有较小的初生重和日增重，同AA和AB基因型比较差异极显著（P〈0．01），3种基因型在初生重和60-210日龄日增重的大小排列顺序一致，为AA〉AB〉胎。因此，推测基因型对个体的初生重和日增重存在一定的影响，选择带有A等位基因的个体有望提高个体的初生重和日增童。

英文摘要：

Single-nucleotide polymorphisms of 5＇ of the MyoG gene were tested using PCR-SSCP in the different pig breeds including Laiwu, Dapuliang, Yimeng Black, and Licha Black pigs, and the effects of the MyoG gene on the birth weight, the 60-day body weight, the 210-day body weight, the daily gain between 60-day and 210- day and the backfat thickness were also analyzed. On the basis of the published DNA sequence of the porcine MyoG gene （U14331）, three pairs of primers were designed, and one polymorphism was found in the PCR product amplified with 5-2 primers, and three genotypes （AA, AB, BB） exist. Amplicons were sequenced, and G→A mutation was detected at 2 080 site. Results ofχ^2 test showed that the Laiwu and the Dapuliang pig breeds differ significantly （P〈0.05） in genotype distribution from the Yimeng Black and Licha Black pig breeds. On the basis of the fixed effect model, significant differences were found in the birth weight among the different MyoG genotypes, whereas no significant differences existed in the 60-day body weight, the 210-day body weight, the daily gain between 60-day and 210-day and the backfat thickness. Using least square analysis, it was seen that individuals of the BB genotype had significantly less （P〈0.01） birth weight and daily gain between 60-day and 210-day than those of the AA and AB genotypes, with the order being AA〉AB〉BB. These results suggest that the genotype has significant effects on the individual birth weight and the daily gain, and that the selection of the A allele is favored with regard to the birth weight and the daily gain.