猪SHP基因外显子1单核苷酸多态性研究

Study on the Single Nucleotide Polymorphism in Porcine SHP Gene Exon 1

微小异源二聚体伴侣基因（Small heterodimer partner gene,SHP）主要在肝脏、心脏、胰脏和脂肪组织中表达,影响脂类在机体内的动态平衡。用PCR-SSCP方法研究猪SHP基因外显子1在5个猪群（长白猪、大白猪、皮特兰猪、金华猪和野猪）中的DNA多态性,结果检测到3种基因型（GG、GA和AA）。χ^2独立性检验结果表明,3种基因型频率分布在各品种间差异显著（P〈0.05）。对纯合子个体测序检测发现,在SHP基因第1外显子内存在一个多态位点（G374A,DQ002896）,且导致编码氨基酸由精氨酸（Arg）替换为组氨酸（His）。对金华×皮特兰F2代资源家系猪进行了该多态片段的基因型鉴定,并分析了不同基因型对猪背膘厚和肌内脂肪含量的遗传效应,结果显示：AA基因型猪肩背膘厚、胸背膘厚、臀背膘厚以及肌内脂肪含量分别比GG基因型猪的低27.0%,30.6%,19.5%和40.9%（P〈0.05）;AA基因型猪6~7肋背膘厚比GA基因型猪的低23.0%（P〈0.05）。

Small heterodimer partner gene is expressed in liver, heart, pancreas and adipose tissue and influences the lipid homeostasis. Three genotypes （GG, GA and AA） of SHP gene exon 1 were identified by PCR-SSCP and their distribution was significant different （P〈0.05） in five pig breeds （Large White, Landrace, Pietrain, Jinhua and Wild boar） by Chi-square analysis. The homozygotes were sequenced and one polymorphic locus （G374A, DQ002896） was found which changed the amino acid from Arg to His. Moreover, association analysis of SHP polymorphism with backfat thickness and intramuscular fat contents was conducted in the F2 generation from the Jinhua× Pietrain resource family. The results showed that the pigs with genotype AA had 27.0%, 30.6%, 19.5% and 40.9% lower backfat thickness at three positions （should, thoraxwaist and buttock ） and intramuscular fat contents respectively than those with genotype GG （P〈0.05）% At 6th-7th rib backfat thickness, the pigs with genotype AA was significantly lower than those with genotype GA by 23.0% （P〈0.05）.