三个远交系豚鼠微卫星遗传结构分析

Analysis of microsatellite genetic structures of three outbred strains of guinea pig

目的评估我校培育的三个远交系豚鼠种群的微卫星遗传结构,筛选不同种群间呈现差异等位基因的微卫星位点,为今后豚鼠遗传育种及应用提供资料。方法使用45对引物通过PCR及电泳技术,对我校三个豚鼠种群的微卫星DNA进行扩增分析,计算各位点等位基因多态性等参数,并筛选出种群间等位基因呈差异变化的微卫星位点。结果所有微卫星位点在豚鼠种群中呈多态性变化,各位点等位基因数2～7不等,平均位点基因数2.29,平均有效基因数1.74;平均期望杂合度为0.39,平均观测杂合度为0.21,多态信息含量的可信范围为0.0739～0.6443,平均PIC为0.32,68.9%的位点呈中度多态性;总Hardy-Weinberg平衡P值平均为0.1734,各种群均为P> 0.05,但对每个位点的基因平衡状态来讲,共有20个位点极显著偏离Hardy-Weinberg平衡,种群平均偏离指数D为-0.407;平均分化指数Fst为0.136,平均基因流Nm为5.835,还阐明了种群间的Nei遗传距离及遗传相似度。结论三个豚鼠种群遗传呈中度多态性变化,种群间平均遗传差异无显著性,遗传相似度较高。群体遗传偏离Hardy-Weinberg平衡较突出,出现严重的近交现象,群体处于中等遗传变异水平,但较高的基因流动阻止了遗传分化发生。分析这些问题的原因,主要是本群体繁殖数量偏小,种子选择范围不广泛等,今后在培育过程中要引起重视。本课题还筛选到与不同种群或毛色豚鼠相关的微卫星位点12个,种群特征性微卫星位点7个,可能用于性状基因定位。

Objective To assess the genetical structures of three outbred strains of guinea pig and screen the microsatellite loci related to different groups of guinea pigs.Methods Using 45 primers,DNA of three groups of guinea pigs was analyzed by PCR and electrophoresis for genetic markers.Then,the polymorphism of these markers was calculated.In addition,the microsatellite locus related to different hair colors was screened in the three groups of guinea pig.Results All microsatellites loci showed polymorphism.The average number of allelic genes was 2.29 per locus and the average value of effective genes was 1.74 per locus.The average expected heterozygosity in total was 0.39.The average observed heterozygosity was 0.21.The average PIC was 0.32,and 68.9%of the loci showed moderate polymorphism.The average P-value of HW was 0.1734,but the inheritance in 20 loci of the total locus diverged extremely significantly from the HW balance.The average deviation index D was-0.407.The differentiation index Fst was 0.136.The gene flow Nm was 5.835.Nie genetic similarity of the three groups was low.Conclusions The genetic structures of the three guinea pig groups show a moderate polymorphism.The genetic differences between the groups are not significant.Inheritance of groups diverged from the HW balance and inbreeding within the groups of guinea pigs is obvious.The main reason for these problems is that the number of guinea pigs used for reproduction is low and there are limitations to the approaches of choosing guinea pig seeds.In addition,12 polymorphic microsatellite loci related to different groups of hair color of guinea pigs and seven specific loci are identified.