三个野生种群马氏珠母贝遗传多样性的RAPD分析

摘要：为了解野生种群马氏珠母贝（Pimctada martensii (Dunker.)）的遗传结构背景和开展遗传改良育种,运用RAPD技术分析了海南三亚（SW）、广东大亚湾（DW）和广西北海（BW）3个野生种群的遗传多样性。采用了18个10碱基的随机引物对3个野生种群进行分析,其中6个引物能扩增出清晰的多态带谱,扩增的DNA片段大小在含0.2~3.0 kb之间。SW、DW和BW 3个种群内的遗传相似性指数分别为0.642、0.672和0.688,Shannon多样性值分别为0.266、0.211和0.174。马氏珠母贝3个野生种群的遗传相似性依次为SW< DW < BW,而遗传多样性依次是SW > DW> BW。DW和SW相对遗传距离为0.104;DW和BW相对遗传距离为0.094;SW和BW相对遗传距离为0.212。讨论了马氏珠母贝野生种群遗传多样性差异的可能原因、种群间杂交子代的杂交优势预测及人工养殖对野生种群遗传结构的可能影响。

Genetic Diversity Analyses of Three Wild Populations of Pinctada martensii (Dunker.) Using RAPD Technique

Abstract : In order to understand genetic diversity of pearl oyster Pinctada martensii （Dunker.）, Random amplified polymorphic DNA (RAPD) analysis was applied in investigating three wild populations,SW population from Sanya,Hainan, DW population from Daya Bay ,Guangdong, and BW population from Beihai,Guangxi. 18 random primers, each containing 10 nucleotide were used. Six of the primers could carry on RAPD amplification,producing the amplified bands of DNA fragments with 0.2 kb to 3.0 kb. All the six primers produced polymorphic products among individuals of both the different populations and the same populations. The genetic similarity index of three wild populations were 0.641 (SW) ,0.672(DW), and 0.688 (BW) respectively, and the Shannon's index of phenotypic diversity(H) in three populations were 0.266 (SW),0.211 (DW) and 0.174(BW) respectively.The genetic similarity of sequence was SW< DW < BW , and the genetic diversity was SW > DW >BW . The relative genetic distances were 0.104 between DW and SW, 0.094 between DW and BW, and 0.212 between SW and BW. The difference of genetic distances in these three wild populations were relative not only to their geographical distances,but also to their different habitants. According to genetic distances between populations, it was predicted that the heterosis of progenies from SW crossing BW, and SW crossing DW were higher than that from BW crossing DW. The result which genetic diversity in BW was significantly lower than that in SW and DW was from the artificial breeding and large scale farming in BW habitant. The reproduction of culturing pearl oysters from the artificial breeding disturbed the diversity of BW population. It will be paid attention to the influence of aquaculture on the genetic structure of wild populations .