甘肃肉羊新品种选育群GDF9基因外显子2多态性及其与产羔性状关联分析

Polymorphism of GDF9 Gene exon2 and Its Relationship with Litter Size Trait of Gansu Meat Sheep New Breed Population

根据GenBank发布的绵羊GDF9基因外显子2的序列设计4对引物,采用PCR-SSCP技术分析GDF9基因外显子2在甘肃肉羊新品种选育群羊中的单核苷酸多态性,并与产羔性状进行关联分析。结果表明,GDF9基因的扩增片段在所检测的新品种群羊中存在PCR-SSCP多态性,检测到3种基因型(AA、AB和BB),而在32只无角陶赛特母羊群中只检测到AA和AB基因型。测序结果显示,GDF9基因编码区第978位碱基发生A→G突变,但没有导致氨基酸的改变;第994位碱基发生G→A突变,导致V变成I(缬氨酸→异亮氨酸)。新品种选育群羊产羔数的最小二乘均值关系为AB>AA>BB,统计分析结果初步表明3种基因型之间差异不显著(P>0.05)。故该区域可能不是影响新品种群羊繁殖力的功能结构区域。

The GDF9 gene was studied as a candidate gene for the high prolificacy of sheep.Four pairs of primers were designed according to the sequence of exon2 of GDF9 gene published in GenBank.Single nucleotide polymorphisms（SNPs）of exon2 of GDF9 gene were detected in Gansu meat sheep new breed population and Poll Dorset by polymerase chain reaction（PCR）-single strand conformation polymorphism（SSCP）.Polymorphism was detected in the amplified region,and three genotype（AA,AB and BB）in Gansu meat sheep new breed population,two genotype（AA,AB）in Poll Dorset were found.The sequence results indicated that there were two single nucleotide mutations（A978G,G994A）in GDF9 gene CDS.The mutation（A978G）did not cause amino acid change,but the mutation（G994A）caused amino acid change（Val→Ile）.The results showed that the lambing numbers with genotype AB was higher than those with genotype AA and BB,and the difference of LSM for lambing numbers among AA,BB and AB was non-significant（P0.05）.Therefore,exon1 of GDF9 gene may not be the functional domain that affects the prolificacy in Gansu meat sheep new breed population.