基于分子标记共祖的亚东鲑育种群体遗传背景分析

Analysis of population genetic background of Salmo trutta fario based on molecular marker coancestry

为明确亚东鲑(Salmo trutta fario)育种群体遗传背景,为今后亚东鲑的育种工作及家系选育提供理论依据,本研究通过分子标记共祖技术,对雅鲁藏布江渔业资源繁育基地的245尾亚东鲑育种群体的遗传背景进行了分析。结果显示:245个个体被分为6个群体,StfA1、StfC2和StfC3群体中多数个体来源于不同祖先,StfB1、StfC1和StfC4群体中多数个体具有单一的祖先来源;245个个体中基因组近交系数大于0.0625的个体比例为19.6%(48/245),其中StfA1群体为36.3%(37/102),StfC2群体为5.9%(3/51),StfC3群体为4.3%(2/47),StfC4群体为50%(6/12);基因组近交系数大于0.125的个体有14个,基因组近交系数大于0.25的个体有1个;6个群体内共有115对个体为全同胞近交类型(CC≥0.25),958对个体为半同胞、祖孙或叔侄近交类型(0.125≤CC<0.25),3653对个体为堂兄妹、半叔侄或曾祖孙近交类型(0.0625≤CC<0.125);6个群体间个体亲缘关系无全同胞近交类型,半同胞、曾孙或叔侄近交类型的个体对为101对;堂兄妹、半叔侄或曾祖孙近交类型的个体对为584对;基因流结果表明StfC3群体和StfC4群体基因交流最大,流向为StfC4群体到StfC3群体,其余各种群间也存在相当程度的基因交流。该亚东鲑繁殖群体遗传多样性水平较低,可能存在一定的种质衰退。StfC1、StfC2、StfC3和StfC4四个群体两两间均达到了近亲繁殖的程度,在今后的亚东鲑育种过程中可做为一个家系使用。

The genetic background of the 245 Salmo Trutta fario breeding population in Yarlung Tsangpo River Fishery Resources Breeding Base was analyzed by molecular marker coancestry technique in this study to clarify the genetic background of Salmo trutta fario breeding population and provide the theoretical basis for future breeding work and family-selected lines of Salmo trutta fario..The results showed that 245 individuals were divided into six groups.The most individuals in group StfA1、StfC2 and StfC3 had different ancestral sources,while most individuals in group StfB1、StfC1 and StfC4 had a single ancestral source.In the 245 individuals,the ratio of the genomic inbreeding coefficient greater than 0.0625 was 19.6%(48/245),with 36.3%(37/102)in the StfA1 population,5.9%(3/51)in the StfC2 population,4.3%(2/47)in the StfC3 population and 50%(6/12)in the StfC4 population.A total of fourteen individuals with a genomic inbreeding coefficient greater than 0.125,with twelve in the StfA1 population and one each in the StfC3 and StfC4 populations;one individual with a genomic inbreeding coefficient greater than 0.25 was in the StfA1 population.A total of 115 pairs of individuals in the six populations were full sibling inbreeding types(CC≥0.25),958 pairs were half-sibling,grandparent-nephew or uncle-nephew inbreeding types(0.125≤CC<0.25),and 3653 pairs were cousin,half-uncle-nephew or great-grandparent inbreeding types(0.0625≤CC<0.125).There were no full sibling inbreeding types among six groups,101 pairs of half-sibling,great-grandson or uncle-nephew inbreeding,and 584 pairs of cousins,half-uncles or great-grandchildren.Gene flow results showed that the gene exchange between StfC3 and StfC4 population was the largest,which flows from StfC4 to StfC3,and there was also a considerable degree of gene exchange among the remaining groups.The level of genetic diversity of Salmo Trutta fario breeding population is low,and there may be some specific germplasm depression.All four populations,StfC1,StfC2,StfC3 and StfC4,reached inbreeding between the two and can be used as a family line in future Salmo trutta fario breeding.