基于G-SSR和EST-SSR标记的鲫6个群体遗传结构分析

摘要

This study investigated genetic diversity and genetic structure of six wild crucian carp populations collected from Heilongjiang River, Yangtze River, Fenghua River and Huaihe River by 8 genome microsatellites (G-SSR) and 8 transcriptome microsatellites(EST-SSR).The mean Na,Ne,Ho,Heand PIC of the eight G-SSR loci were 22,12.9, 0.769, 0.893 and 0.879, respectively. Fstvalues ranged from 0.008 to 0.085, indicating that there were different degrees of genetic differentiation among the six wild crucian carp populations, among which two populations from the Hei-longjiang River system were different from all the others. There was no significant genetic differentiation among the four populations in the Yangtze River, Fenghua River and Huaihe River. The Nei's genetic distances of six wild cru-cian carp populations were between 0.203—0.701. UPGMA cluster analysis and Bayesian analysis supported that six crucian carp populations could be divided into two large branches with two populations from Heilongjiang water sys-tem as one group while the others as another group.The average Na,Ne,Ho,Heand PIC of the eight EST-SSR loci were 19, 9.5, 0.728, 0.870 and 0.855 respectively. The Fstvalues and Nei's genetic distances among the six populations were between 0.005—0.084 and 0.117—0.683, respectively. Genetic differentiation analysis, UPGMA cluster analysis and Bayesian analysis based on EST-SSR markers also separated six populations of crucian carp into two major groups: the Heilongjiang water system group as well as the Yangtze River, Fenghua River and the Huaihe River system group. Based on G-SSR and EST-SSR markers,the average polymorphism information content(PIC)of the six crucian carp populations ranged between 0.786—0.864 and 0.761—0.833, respectively, indicating that all the six wild crucian carp populations had a high genetic diversity. Although the polymorphism of the EST-SSR markers was slightly lower than that of the G-SSR markers, the two types of SSR markers revealed similar genetic structure and pattern of differentia-tion for crucian carp in three major waters of China. This study provides basic and new information for the conserva-tion of crucian carp germplasm resources and the evaluation of EST-SSR markers in genetic studies of fish populations.%研究同时利用非编码区和编码区微卫星标记(G-SSR和EST-SSR)分析黑龙江、长江、奉化江及淮河水系共6个野生鲫(Carassius auratus)群体的遗传多样性及遗传结构,并比较2类不同来源SSR用于鲫群体遗传多样性分析的差异.8个G-SSR标记在6个鲫群体中检测到173个等位基因,平均Na、Ne、Ho、He以及PIC分别为22、12.9、0.769、0.893和0.879, 群体间Fst值介于0.008—0.085, 其中来自黑龙江水系的2个群体与其余水系的所有群体均达到或接近于中等程度的遗传分化, 而长江、奉化江和淮河水系4个群体间的遗传分化程度不明显.Nei's遗传距离介于0.203—0.701; 根据遗传距离所绘制的UPGMA聚类图将6个鲫群体划分为2个大分支,其中来自黑龙江水系的2个群体聚为一枝, 其余水系群体聚为另一枝.贝叶斯分析也支持这一结果, 将6个鲫群体划分为2个最佳理论群.利用8个EST-SSR标记在6个鲫群体中共检测到155个等位基因, 平均Na、Ne、Ho、He以及PIC分别为19、9.5、0.728、0.870和0.855;群体间Fst值和Nei's遗传距离分别介于0.005—0.084和0.117—0.683; 基于EST-SSR标记的UPGMA聚类分析和贝叶斯分析也将6个鲫群体划为两大类群: 黑龙江水系群体;长江、奉化江和淮河水系群体.G-SSR和EST-SSR标记检测6个鲫群体的平均多态信息含量(PIC)分别为0.786—0.864和0.761—0.833.研究结果显示: 6个野生鲫群体均具有较高的遗传多样性, 但黑龙江水系群体多样性低于其他水系群体; 尽管EST-SSR标记的多态性略小于G-SSR标记, 但是2类微卫星标记均揭示了相似的鲫群体遗传结构和分化格局.研究结果对鲫种质资源的保护和EST-SSR标记在鱼类群体遗传学研究价值的评价提供了新的信息.