中文摘要：

采用PCR-SSCP方法检测胰岛素样生长因子2（insulin-like growth factor 2,IGF2）基因外显子7,8,9的多态性,并分析其对初生重、断奶重、6月龄重和6月龄背膘厚的遗传效应。根据猪IGF2基因的DNA序列（AY044828）设计3对引物,结果在Ex8引物对扩增的片段上发现了多态性,并对纯合子进行测序,发现exon8的53位存在C→T转换,且检测到3种基因型（AA、AB、BB）。统计结果表明,3种基因型在各品种中的分布不一致,长白猪与大白猪比较,莱芜猪与大薄莲猪比较,沂蒙黑猪和里岔黑猪比较差异不显著（P〉0.05）;其他猪种间基因型分布的差异均显著（P〈0.01）。固定效应模型分析结果表明,初生重和6月龄背膘厚基因型间差异显著（P〈0.05）,而断奶重和6月龄重基因型间差异不显著（P〉0.05）。最小二乘分析结果表明,BB基因型个体同AA和AB基因型个体比较初生重的差异显著（P〈0.05）,3种基因型在初生重的大小排列顺序为AB〉AA〉BB;AA基因型个体同AB和BB基因型个体比较6月龄背膘厚的差异显著（P〈0.05）,3种基因型在6月龄背膘厚的大小排列顺序为BB〉AB〉AA。因此,推测IGF2基因对个体的初生重和胴体瘦肉率存在一定的影响,将IGF2基因应用于猪育种过程中的标记辅助选择可以加快猪的育种进程。

英文摘要：

Single nucleotide polymorphisms of the exon7, 8, 9 of the porcine IGF2 gene were tested using PCR-SSCP. Genetic effects of the IGF2 gene on birth weight, weaning weight, six-month weight and six-month backfat thickness were analyzed. On the basis of the published DNA sequence （AY044828） of the porcine IGF2 gene, three pairs of primers were designed, and one polymorphism, three genotypes were found in the PCR product amplified with Ex8 primers. C→T transi- tion at 53 site of exon8 was detected by sequencing the homozygotes. The results showed that： firstly, the genotype distribution was not consistent among the different pig breeds. No significant differences （P 〉 0.05） were found in the genotype distribution when compared the Landrace with the Large White, the Laiwu with the Dapuliang, and the Yimeng with the Licha Black pig breeds, whereas significant differences （P 〈 0.01） were found among other tested pig breeds in the genotype distribution. Secondly, on the basis of the fixed effect model, significant differences （P 〈 0.05） were found in birth weight and six-month backfat thickness, whereas no significant differences （P 〉 0.05） existed in weaning weight and six-month weight. Thirdly, using least square analysis, it was shown that individuals of the BB genotype have significantly lower （P 〈 0.05） birth weight than those of AA and AB genotypes, with the order being AB 〉 AA 〉 BB ; Individuals of the AA genotype have significantly lower （P 〈 0.05） six-month backfat thickness than those of AB and BB genotypes, with the order being BB 〉 AB 〉 AA. These results suggest that IGF2 gene has significant effects on individual birth weight and backfat thickness. The IGF2 gene can be used in marker-assisted selection to accelerate the breeding progress.