新型湘云金鳙遗传多样性的RAPD及微卫星分析

RAPD and Microsatellite Analysis of Red Bighead Carp(Aristichthys nobilis)

湘云金鳙是本实验室经过近十年的工作选育出来的,该种鱼通体金红色,肉质鲜嫩,生长速度快,是一种很有价值的养殖鱼种和实验材料。随机选取12尾湘云金鳙(RBC)和12尾来自湘江流域的普通鳙鱼BC(作为对照)进行RAPD和微卫星分析。在优化RAPD检测条件基础上,从230个随机引物中筛选出来的45个扩增较好且多态性强的引物对这两个群体的DNA多态性及分子标记进行了分析。结果显示在45个随机引物的扩增谱带中找到了2个引物(S20、S46)的特异扩增谱带,可以作为RBC和BC间的分子遗传标记。普通鳙鱼群体内个体之间的遗传距离范围从0.04-0.13,群体内的平均遗传距离为0.075,而湘云金鳙群体内个体之间的遗传距离范围从0.02-0.35,群体内的平均遗传距离为0.139。这表明湘云金鳙群体遗传多样性明显强于普通鳙鱼群体。从32对微卫星标记中筛选9对微卫星标记用于两个群体24个个体的扩增。平均每个微卫星位点在湘云金鳙群体和普通鳙鱼群体中检测到的平均有效等位基因数分别为2.44和1.89。普通鳙鱼群体的平均杂合度期望值(0.34)和平均杂合度观测值(0.39)要比湘云金鳙群体的平均杂合度期望值(0.51)和平均杂合度观测值(0.54)的小得多。由此可见,RAPD和微卫星这两种方法得出的结果是一致的,普通鳙鱼群体的遗传多样性比湘云金鳙群体低。此外,通过RAPD和微卫星对两种鳙鱼遗传多样性水平的分析,为鳙鱼种质保护提供科学证据,为鳙鱼良种选育提供了更多的遗传学背景资料。

Genetic variation was comparatively analyzed between the Red bighead carp （RBC） population and the bighead carp （BC） population of aquaculture strains originating from xiangiiang river used as the control, using random amplified polymorphic DNA （RAPD） assay and microsatellite analysis. The specific fragments for RBC and BC population was detected by 520 and S46 respectively： The average genetic distances of BC ranged from 0.04 to 0.13 with a mean of 0. 075. And the average genetic distances of RBC ranged from 0.02 to 0.35 with a mean of 0. 139. The average genetic distances estimated by Lynch＇ s index of BC population were significantly lower than those of RBC population. Whereas the average genetic distances between BC and RBC ranged from 0.06 to 0.37 with a mean of 0. 123. The mean number of alleles per microsatellite locus （ 1. 89 ） in BC population was considerably lower than that （ 2.44 ） in RBC population. The average observed （0.34） and expected heterozygosity （0.39） in BC population were lower than those （0.54 and 0.51, respectively） in RBC population, indicating that the RBC presented higher genetic diversity than the BC. The resuits from RAPD assay and microsatellite analysis were in agreement with each other, that is to say, the BC presented lower level of polymorphism than RBC. In addition, the RAPD and SSR analysis of genetic diversity of two kinds of bighead carp, provided scientific evidence and more information on the genetic background for bighead carp germplasm protection.