中文摘要：

采用PCR-SSCP方法检测猪胰岛素样生长因子2（insulin-like growth factor2,IGF2）基因外显子3多态性,分析其对初生重、断奶重、6月龄重和背膘厚的遗传效应.根据猪IGF2基因的DNA序列（AY044828）设计引物,结果在其扩增片段上检测到多态性,对纯合子进行测序,发现IGF2-ex3-A36T和IGF2-ex3-G109A两个多态性位点,并且这2个多态性位点完全连锁,检测到3种基因型（A36A/G109G,A36T/G109A和T36T/A109A）.统计结果表明,基因型在各品种中分布不一致,长白猪和大白猪与莱芜猪、大薄莲猪、沂蒙黑猪和里岔黑猪比较基因型分布差异极显著（P〈0.01）;其它猪种间基因型分布差异均不显著（P〉0.05）.固定效应模型分析结果表明,初生重和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,A36A/G109G基因型个体同A36T/G109A和T36T/A109A基因型个体比较初生重和背膘厚的差异显著（P〈0.05）,3种基因型初生重的大小排列顺序为A36A/G109GA36T/G109A〉T36T/A109A.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,将可以改善猪肉品质,加快猪的育种进程.

英文摘要：

Genetic variation in exon 3 of the porcine insulin-like growth factor 2 （IGF2） gene was investigated via PCR-SSCP. Genetic effects of IGF2 gene on birth weight, weaning weight, weight at six-month old and backfat thickness were analyzed. On the basis of a published porcine IGF2 gene DNA sequence （AY044828）, primers were designed, and two polymorphisms （IGF2-ex3-A36T and IGF2-ex3-GIOgA） were detected by sequencing the homozygotes. These two polymorphism sites were absolutely linked and three genotypes（A36A/ G109G, A36T/G109A and T36T/A109A）existed. The results show that the genotype distribution was discrepancy among the tested pig breeds. Significant differences （ P 〈 0.01 ） were found for the genotype distribution while compared the exotic pig breeds （Landrace and Large White） with native pig breeds （Laiwu, Dapulian, Yimeng black and Licha black pigs）. On the basis of the fixed effect model, significant differences （ P 〈 0.05） were found in birth weight and backfat thickness, whereas no significant differences （ P 〉 0.05） existed in weaning weight and weight at six-month old. By least square analysis, it was shown that individuals of the A36A/G109G genotype have significantly lower （P 〈 0.05） birth weight than those of A36T/G109A and T36T/A109A genotypes, with the order A36A/G109G 〈 A36T/G109A 〈 T36T/A109A; Individuals of the A36A/G109G genotype have significantly higher （P 〈 0.05） backfat thickness than those of A36T/G109A and T36T/A109A genotypes, with the order A36A/G109G 〉 A36T/G109A 〉 T36T/A109A. 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 provide significant improvements for meat quality and to accelerate the breeding progress.