绵羊Lpin2基因多态性及其与尾型和屠宰性状的关联分析

试验旨在研究Lpin2基因遗传变异对绵羊尾型和屠宰性状的影响。以两品种脂尾型绵羊广灵大尾羊和小尾寒羊为研究对象，采用DNA直接测序法检测Lpin2基因5'非编码区部分序列的单核苷酸多态性（SNPs），并分析其与尾型及屠宰性状的关联性。结果发现，Lpin2基因5'非编码区起始密码子上游约1 200 bp的DNA序列中存在3个SNPs，即NC_019480.2:g.－663 dup ATT（SNP1）、g.－388 T > C（SNP2）和g.－330 T > G（SNP3），其中SNP1为三核苷酸ATT重复扩展短串联重复序列（STR）的拷贝数变异（CNV），在广灵大尾羊中的突变频率显著高于小尾寒羊（P<0.05），显著降低了广灵大尾羊的胴体重与屠宰率（P<0.05），对小尾寒羊的屠宰性状无显著影响（P>0.05）。SNP2和SNP3构成单倍型块，形成的单倍型对各性状无显著影响（P>0.05）。试验结果可为绵羊肉质性状的标记辅助选择提供参考依据。

Polymorphisms of Lpin2 Gene and Its Association with Tail Type and Slaughter Traits in Sheep

This study was aimed to explore the effects of genetic variations of Lpin2 gene on tail type and slaughter traits in sheep. Two breeds of fat-tailed sheep such as Guangling Large Tailed sheep and Small Tailed Han sheep were chosen to identify the single nucleotide polymorphisms (SNPs) in 5' non-coding region of Lpin2 gene by using direct DNA sequencing, and the associations between SNPs and tail type and slaughter traits were analyzed. The results showed that three novel SNPs were found in 5' non-coding region about 1 200 bp upstream sequence from start codon ATG in Lpin2 gene, namely NC_019480.2: g.－663 dup ATT (SNP1), g.－388 T > C (SNP2) and g.－330 T > G (SNP3), sequencing data revealed that the trinucleotide ATT repeat expansion at SNP1 was cope number variation (CNV) of short tandem repeats (STR), the mutation frequency was significant higher in Guangling Large Tailed sheep than that in Small Tailed Han sheep (P<0.05), and caused the significant decreasing in carcass weight and dressing percentage in Guangling Large Tailed sheep (P<0.05), however this variation exhibited non-significant effects on the slaughter traits in Small Tailed Han sheep (P>0.05). SNP2 and SNP3 could be constructed into a haplotype block while the haplotypes didn't significantly affect the examined traits in two sheep breeds. This finding would provide references for marker assisted selection of the sheep meat quality traits.