摘要
运用微卫星标记对大竹蛏（Solen grandis）辽宁丹东（DD）、河北秦皇岛（QHD）、山东日照（RZ）、江苏吕四（LS）和广西北海（BH）近海5个不同地理野生群体共计150个样品进行了遗传多样性分析。结果表明：14个位点多态信息含量范围为0.696～0.853,均呈现高度多态性,每个位点检测到的等位基因数8～22个,共检测到199个等位基因,平均等位基因数为14.2,等位基因丰富度为11.05,5个群体的期望杂合度分别为0.769（DD）,0.791（QHD）,0.826（RZ）,0.815（LS）,0.785（BH）,观察杂合度分别为0.837（DD）,0.812（QHD）,0.875（RZ）,0.809（LS）,0.858（BH）,表明各群体处于较高的遗传多样性水平。Hardy-Weinberg 平衡检验显示,仅有 Sg16位点在丹东群体显著偏离平衡,其余位点在5个群体均正常,表明各群体遗传较稳定,处于平衡状态。5个群体间的遗传距离在0.1412～0.3409, DD和 QHD 的遗传距离最小, DD 和 BH 的遗传距离最大；基于 Da 遗传距离构建的 UPGMA 聚类树显示,距离相邻的DD、QHD 渤海湾群体聚为一支, RZ、LS 黄海群体聚为另一支,最后与南海群体 BH 聚在一起,聚类结果与地理位置密切联系,基于贝叶斯遗传聚类得到了相同的结果。分析群体间的 Fst 值可知,两两群体间的 Fst 值在0.0391～0.0947,群体间产生了中等程度的遗传分化,并且达到了极显著水平（P=0.0001）。由此可见,中国沿海各地理群体野生大竹蛏种质遗传多样性较为丰富,但不同群体间存在显著的遗传分化,故各增殖放流海区应当加强对放流苗种及繁殖亲本的种质检测,防止异地繁养等人为因素对大竹蛏各野生种群遗传结构造成破坏。
The grand jackknife clam Solen grandis （Dunker, 1861） is a commercial marine bivalve that is found in coastal waters of China, Japan, and Korea from the shallow subtidal to depths of 20 m. It has high nutritive and medical value according to traditional Chinese medicine. In addition, it is adaptable and has high growth rates and great market potential. Currently, this clam is only available from natural sources. Over the last few decades, however, overfishing and environmental pollution have caused dramatic declines in natural stocks of S. grandis, and production is low and unstable. Fortunately, methods of artificial breeding and cultivation of the jackknife clam are developing. Previous studies on S. grandis focused primarily on morphological and ecological characteristics, allozyme analysis, and evalua-tion of its nutrition components. Little is known about the molecular ecology of S. grandis or its genetic background. Thus, it is important to evaluate genetic differences among populations along the coast of China. In this study, 14 mi-crosatellite DNA markers were used to examine the genetic diversity and differentiation among five wild populations of the grand jackknife clam. A total of 150 samples were collected from Dandong （DD） in Liaoning Province, Qinhuang-dao （QHD） in Hebei Province, Rizhao （RZ） in Shandong Province, Lyusi （LS） in Jiangsu Province, and Beihai （BH） in Guangxi Province. Comparisons of 199 alleles among the five populations showed that, in the fourteen loci, polymor-phism information content （PIC）values ranged from 0.696 to 0.853 with high polymorphism. The number of alleles ranged from 8 to 22 and the average number （AM） and richness（AR） of alleles were 14.2 and 11.05, respectively. Ex-pected （He） and observed heterozygosity （Ho） ranged 0.769–0.826 and 0.809–0.858, respectively, suggesting high levels of genetic diversity in all populations. Only the Sg16 locus in the DD population deviated significantly from Hardy-Weinberg equilibrium, further indicating stability in the genetic diversity of all populations. The genetic distance among the five populations ranged from 0.141 2 to 0.340 9, with minimum and maximum distances between DD and QHD and between DD and BH, respectively. The UPGMA tree indicated highest similarity among geographically close populations, clustering DD with QHD and RZ with LS, the structure of which was confirmed by Bayesian cluster analysis. The Fst were 0.039 1– 0.094 7, suggesting a moderate degree of differentiation among the five wild popula-tions. Overall, the results suggest a high level of genetic diversity and differentiation among five grand jackknife clam populations from geographically distinct locations along the coast of China. Precaution should be taken to protect the germplasm of this species, particularly when designing stock enhancement programs.
出处
《中国水产科学》
CAS
CSCD
北大核心
2015年第4期740-748,共9页
Journal of Fishery Sciences of China
基金
江苏省自然科学基金(BK2012235)
江苏省"六大人才高峰"(2013-NY-013)
浙江省近岸水域生物资源开发与保护重点实验室开放课题(J2013008)
关键词
大竹蛏
微卫星
野生群体
遗传多样性
Solen grandis
microsatellite
wild population
genetic diversity
