| 摘要: |
| 运用微卫星DNA技术，以中国对虾渤海湾群体(BH)、辽东湾群体(LD)和海州湾群体(HZ)的3个野生群共计60个个体为实验材料，进行了7个基因位点的遗传参数分析。同时对7对微卫星引物的多态性信息含量(PIC)进行了评估，EN0021位点提供的信息含量低于0.5，其他6对微卫星引物的PIC值均在0.5以上，适于应用于中国对虾的群体分析。结果表明，这7个微卫星位点在中国对虾3个地理群60个样品的分析中共获得了56个等位基因，对3个野生群体的7个基因位点共计21个群体位点进行了杂合度观测值(Ho)和杂合度期望值(He)计算；在Hardy-Weinberg平衡条件下，进行了P检验，发现BH和HZ各有1个群体位点发生平衡偏离，而LD有1个群体位点发生平衡偏离，还有2个群体位点已发生显著平衡偏离。但除此之外，对3个地理群间的遗传分化指数 值进行的计算结果表明，BH和LD之间遗传分化较弱，HZ与另2个地理群间则产生了中等程度的分化。从变异贡献率来看，有92.83%的遗传变异来自个体之间，只有7．17％的遗传变异来自群体之间。经过UPGMA聚类，发现BH群体和LD群体的亲缘关系较近，而HZ群体与前两者亲缘关系较远。 |
| 关键词: 中国对虾, 地理群体, 微卫星DNA, 多态性分析 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目，30271038号；国家重点基础研究发展规划项目，1999012007号；国家“863”计划资助项目，2003AA603021号 |
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| GENETIC DIVERSITY IN THREE WILD POPULATIONS OF SHRIMP FENNEROPENAEUS CHINENSIS IN YELLOW AND BOHAI SEAS AS REVEALED BY MICROSATELLITE DNA |
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LIU Ping, MENG Xian-Hong, HE Yu-Ying, KONG Jie, LI Jian, WANG Qing-Yin
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Yellow Sea Fisheries Research Institute，Chinese Academy of Fishery Sciences
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| Abstract: |
| The Microsatellite DNA technique was used to estimate genetic diversity and genetic differentiation in three wild populations of shrimp Fenneropenaeus chinensis, three of which were collected from the Bohai Sea Bay (BH), Liaodong Bay (LD) and Haizhou Bay (HZ), respectively. Genomic DNA was extracted from 60 samples for the three wild populations. PCR was performed in a 25μl reaction and isolated by electrophoresis on a 8% denaturing polyacrylamide gel and visualized by silver staining. The purpose of the study was to provide theory basis for the continuable utilization of germplasm resources and population plot of F.chinensis.
Results showed: 7 polymorphic loci were screened electrophoretically for genetic variation of the three wild populations. PIC (Polymorphic Information Content) value per locus was more than 0.5 except for locus EN0021 (PIC = 0.3174) which was not the same with the analysis of population genetics and the construction of genetic linkage map. 56 alleles were acquired from the three geographical populations represented by 60 samples at 7 microsatellite DNA loci. The numbers of alleles in different loci ranged from 3 to 16, with on average 7.625, the highest numbers of alleles were from locus EN0033(16)followed by RS0683(12), RS0859(7), locus EN0018, EN0201 and RS1 101 acquired 6 alleles, respectively, locus EN0021 only acquired 3 alleles.
The observed heterozygosity (Ho) and the expected heterozygosity (He) were calculated based on frequencies of genotypes and alleles of each microsatellite locus, the average Ho value was the highest with BH (Ho=0.7000, He=0.7273) followed by HZ (Ho=0.6929, He=0.7553) and LD (Ho=0.5857, He=0.7184). In all populations, the average He value was higher than the average Ho value. The test of P values showed that 1 locus departed from the Hardy-Weinberg equilibrium in each population of the BH and HZ, 2 loci departed prominently from the Hardy-Weinberg equilibrium except that 1 locus departed from the Hardy. Weinberg equilibrium in the population of LD, but as a whole, the three wild populations were in a balanced condition according to the average value of P (P>0.4).
Both genetic distance and genetic similarity evaluated between populations according to the method by Nei (1972) showed that BH and LD were of the shortest genetic distance, followed by LD and HZ. BH and HZ were of the longest genetic distance. Genetic diversity followed the same trend. Cluster analysis of the three wild populations performed with UPGMA (unweighted pair group method with arithmetic mean) confirmed the closer linkage between BH and LD than their individual distances to HZ.
The degree of population differentiation between the three wild populations using AMOVA model in ARLEQUIN showed that BH and LD have the lowest value of diversity coefficient (Fst) indicating only the slightest differentiation between the populations of BH and LD. The degree of population differentiation was moderate between I-IZ and one of
the remaining two geographic populations(Fst > 0.5). For the three wild populations, variation was mostly due to within populations (92.83%) rather than among populations (7.17%) according to the contribution rate of variation. |
| Key words: Fenneropenaeus chinensis, Geographic populations, Microsatellite DNA, Polymorphic analysis |
