放流三疣梭子蟹遗传多样性和贡献率初步研究

近年来我国沿海三疣梭子蟹自然资源明显下降,为恢复现有资源,辽宁省自2012年开始,连续实施了4年大规模人工放流工作。在目前的增殖放流中,为检测参与繁殖的三疣梭子蟹亲本和即将放流的子代间的遗传差异以及亲本对其子代的繁殖贡献率水平,利用10对具有丰富遗传多态性的微卫星分子标记,分别对9只三疣梭子蟹雌性亲本和179只即将放流的子代进行了遗传多样性分析及亲子鉴定。结果发现,子代的平均观测杂合度、平均期望杂合度和平均多态性信息含量数值均低于参与繁殖的雌性亲本,亲本和放流子代之间在观测杂合度、多态性信息含量参数方面并无显著差异(P0.05),但期望杂合度遗传参数存在显著差异(P0.05),子代的遗传多样性较雌性亲本呈下降的趋势。使用4个微卫星分子标记时,累积排除率≥0.998,亲子鉴定的准确率为56.98%;微卫星分子标记为6个时,累积排除率≥0.9999,准确率达到97.21%;当使用8个微卫星分子标记鉴定时,准确率达100%。同时发现,9只雌性亲本对子代均有贡献,最高为29.61%,最低为3.35%,不同亲本之间的贡献率存在显著差异(P0.05)。研究表明,微卫星可以作为有效的标记手段用于三疣梭子蟹增殖放流遗传评估中。上述试验结果将为我国三疣梭子蟹增殖放流的科学发展提供基础资料。

Parental Contribution and Genetic Diversity between Broodstock and Offsprings in Swimming Crab (Portunus trituberculatus) Releasing into Natural Waters

The releasing and enhancement of swimming crab (Portunus trituberculatus) stock has been car‐ried out since 2012 as the wild resources is decreased significantly in recent years .We used 10 microsatel‐lite markers to estimate genetic diversity ,the Probability of Exclusion (PE) ,paternity test accuracy ,and the parental contribution of 9 female parents ,based on 179 offsprings of swimming crab to consider the difference in contribution to reproduction between parents in the effectiveness of enhancement programs .It was found that there were significantly lower average heterozygosity and polymorphic information content (PIC) ,observed heterozygosity (Ho)in offsprings than those in the female parents ,with significant differ‐ence in excepted heterozygosity (He)between broodstock and offsprings (P<0 .05 ,Wilcoxon signed‐rank test) and without significant difference in Ho and PIC (P>0 .05) ,showing lower genetic diversity in the offsprings than in their female parents .The 4 microsatellite markers analysis revealed that the PE was ≥0 .998 and accuracy was 56 .98% .Using 6 microsatellite markers ,however ,the PE was ≥0 .9999 and ac‐curacy was 97 .21% ,and by using 8 microsatellite markers ,the accuracy was 100% ,indicating that the accuracy was increased with an increase in the number of microsatellite markers .Nine female parents were all found to be contributed in the production of offspring tested in this experiment ,with the maximal con‐tribution of 29 .61% and the minimal of 3 .35% ( P<0 .05 ,Nonparametric chi‐square test ) .T he findings indicate that the microsatellite markers as an effective means can be used for assessment of the genetic di‐versity of swimming crab in enhancement programs ,and that provide scientific basic data for the scientific development of crab breeding and releasing in China .