Leptin基因多态性与绵羊季节性发情的相关分析

Analysis of the Relationship Between Polymorphism of Leptin and Seasonal Estrous in Sheep

根据leptin基因在GenBank中的已知序列设计两对引物,采用PCR-SSCP技术在常年发情的湖羊和季节性发情的阿勒泰羊群体中进行单核苷酸多态性(SNPs)检测,对筛查到的SNP位点进行基因型与绵羊季节性发情的关联分析。结果表明,与湖羊相比,阿勒泰羊leptin基因第1内含子上有3个连续碱基TTG的插入和C/T碱基突变;第3外显子3上发生G/T碱基突变,编码氨基酸由缬氨酸变成亮氨酸。Leptin外显子2扩增片段上检测到AA、AB、BB三种基因型,BB基因型在阿勒泰羊群体中属于优势基因型;对两个群体进行基因型频率独立性χ2检验,差异极显著(P<0.001),说明BB基因型是影响季节性发情的有利基因型。研究结果提示,绵羊品种中Leptin基因序列的差异性可能是造成绵羊季节性发情的原因之一,可作为常年发情绵羊品种选育的辅助标记。

According to the known sequence of leptin gene from GenBank, two primers were designed. The single nucleotide polymorphisms（SNPs）of the nonseasonal estrus Hu sheep and seasonal estrus Altay sheep were detected using PCR-SSCP assay. Then, the screening SNPs was subjected to the relative analysis of genotype and seasonal estrus. The results showed that three consecutive bases TTG inserted and C / T mutated intron 1 of leptin in Altay sheep, and G / T mutation in exon 3 resulted in the replacement of valine by leucine in contrast with the Hu sheep. Three genotypes AA, AB, BB were detected on the amplified fragment of the exon 2, the genotype BB was dominant in Altay. The genotype distributions were significantly different（P0.001）between two groups, especially demonstrated that genotype BB was benefit for seasonal estrus. In conclusion, the sequence difference of Leptin in different sheep breeds may be one possible reason leading to nonseasonal or seasonal estrus, which can be used as an assistant marker for nonseasonal estrus breeding.