青鱼生长相关SNP标记在不同地理群体中的验证

Verification of black carp growth-related SNP marker in different geographical populations

单核苷酸多态性分子标记(single nucleotide polymorphism,SNP)是目前常用的分子标记辅助育种的工具之一。本研究在前期构建的青鱼(Mylopharyngodon piceus)高密度连锁图谱和QTL定位结果的基础上,利用体质量QTL区间中的2个SNP标记在3个青鱼群体中进行验证,目的是为了检测通过QTL定位得到的SNP是否存在并能应用于其他地理群体,利用对分子标记的侧翼序列进行基因型组成分析、遗传多样性分析及中性检验等方法,对3个群体的2个SNP侧翼序列进行分析。遗传多样性结果显示,snp8107的扩展片段的单倍型多样性(H)在邗江群体、湘江群体和石首群体中分别为0.782、0.515和0.497;各位点的观测杂合度(H)为0.067~0.533,平均为0.239;期望杂合度(H)为0.127~0.506,平均为0.306;多态信息含量(PIC)为0.117~0.374,平均为0.246。中性检验显示3个群体在历史上可能发生过瓶颈效应导致稀有等位基因丢失的现象,结合遗传多样性结果推测,邗江群体在经历瓶颈效应后保留下来的稀有等位基因更多,最终得出结论邗江群体是适合进行遗传改良的最优群体。

Single nucleotide polymorphism(SNP)is one of the commonly used molecular marker-assisted breeding tools.In this study,based on the high-density linkage map and QTL mapping results of black carp(Mylopharyngodon piceus)in previous study,two SNP molecular markers at the body weight QTL interval were used to verify in three populations.The purpose of this study was to verify whether the SNP from previous study exists and can be applied to other geographic groups.Two SNP molecular markers flanking sequences were analysed by using performing genotype composition analysis,genetic diversity analysis and neutrality test in three geographic groups.The results of genetic diversity showed that the haplotype diversity(H)of the extended fragment of snp8107 was 0.782,0.515 and 0.497 in Hanjiang population,Xiangjiang population and Shishou population,respectively;the observed heterozygosity(H)of each locus was from 0.067 to 0.533;The expected heterozygosity(H)ranged from 0.127 to 0.506,with an average of 0.306,and the polymorphic information content(PIC)ranged from 0.117 to 0.374,with an average of 0.246.The neutral test for three populations showed that the bottleneck effect may have occurred in history which led to loss of the rare alleles.Combined with the results of genetic diversity,we speculated that the Hanjiang population retained more rare alleles after experiencing the bottleneck effect.It was concluded that the Hanjiang population was the best variety suitable for genetic improvement.