基于微卫星标记的钱塘江上游黄尾鲴增殖放流效果及其潜在遗传风险评估

为评估钱塘江上游黄尾鲴的增殖放流效果和潜在遗传风险，本实验利用已开发的11对微卫星引物，基于亲子鉴定技术对钱塘江上游增殖放流黄尾鲴的资源贡献率进行估算，同时开展黄尾鲴养殖群体和野外群体的遗传多样性比较，评估其增殖放流的遗传风险。结果显示，33尾繁殖亲本群体和105尾回捕群体的平均等位基因数(Na)为8.64，平均观测杂合度(Ho )为度为0.708，平均期望杂合度(He)为0.739，平均多态信息含量(PIC)为0.703，11对微卫星引物多样性较高。亲缘关系分析表明，11座位累计非亲权（CEP）排除率达到99.999 98 0 %，在回捕的105尾黄尾鲴个体中，5尾回捕个体被确认为放流的子代，对野外群体的资源贡献率为4.76%。黄尾鲴养殖群体和野外群体均具有较高的遗传多样性，且群体内各个遗传参数相差较小，遗传多样性水平相近；分子方差分析（AMOVA）表明，遗传变异主要来自于群体内（95.92%），遗传分化系数FST为0.053 59 ，群体间的Nm 为4.42，属于低等程度的分化，基因交流无障碍。综合分析表明，钱塘江增殖放流的黄尾鲴具有良好的资源恢复效果，且无放流带来的潜在遗传风险。

Stock enhancement effect and potential genetic risks of Xenocypris davidi by molecular markers in the upper reaches of Qiantang River, China

Xenocypris davidi is one of the most important economically freshwater fish in China. In recent decades, owing to the construction of dams, overfishing, habitat degradation, pollution of water, and other human disturbances, the number and biomass of X. davidi local populations declined sharply. On the other hand, X. davidi can effectively restrain the aggravation of eutrophication and control the abnormal proliferation of algae. To restore fishery resources of X. davidi and improve water quality, restocking enhancement activities of X. davidi have been constructed in natural waters since the 1980s. It is urgent to carry out the evaluation of the effect of restocking enhancement of X. davidi, as well as the potential genetic risk assessment of breeding population to wild population of X. davidi under large-scale proliferation and release. However, there was rarely report on the effect of restocking enhancement of X. davidi. In order to assess the effect of restocking enhancement of X. davidi and provide guidance and suggestions for the breeding and releasing of X. davidi in Qiantang River, the potential genetic risks of X. davidi in the upper reaches of Qiangjiang River were evaluated by using 11 polymorphic microsatellite loci. We collected 33 breeding parents and 105 recaptured individuals. Microsatellite DNA molecular marker technology was used. The number of mean alleles(N a) ,the mean observed (Ho) , mean expected heterozygosity (He) and mean polymorphic information content (PIC) were 8.64, 0.708, 0.739 and 0.703, respectively. It was proved that 11 pairs of microsatellite primers as an effective tool for parentage identification. The combined non-exclusion probability (CEP) of 11 loci was 99.999 980 % by Cervus software. Five individuals were confirmed to be released. The return capture rate of the offspring is 4.76%. The comparative analysis of genetic diversity between the cultured and wild populations of X. davidi showed that the two populations had high genetic diversity, and the genetic parameters of population differed little, indicating that their genetic diversity levels were close; AMOVA analysis showed that genetic variation mainly from within the population (95.92%), the genetic differentiation coefficient FST is 0.053 59, and the gene exchange value (Nm) was 4.42, the results showed that it was a low degree of differentiation and gene communication was barrier-free. So our study suggested that the stock enhancement of X. davidi in Qiangjiang River had produced a good resource recovery effect, and there was no potential genetic risk caused by the release. In the following studies, on the basis of making full use of microsatellite genotype data, we should strengthen the long-term and continuous tracking of the release population and the field population, so as to provide basic support for the scientific evaluation of the stock enhancement and the conservation of seed resources of X. davidi.