【作者】 吕红丽；

【导师】 侯林；

【作者基本信息】 辽宁师范大学 ， 海洋生物学， 2004， 硕士

【摘要】 四角蛤蜊(mactraveneriformis)属于软体动物门(Mollusca)瓣鳃纲(Lamellibranchia)真瓣鳃目(Eulamellibranchia)异齿亚目(Heterodnta)蛤蜊科(Mactridae), 是一种广泛分布于我国沿海(以辽宁、山东为最多)的经济贝类。虽然国内外对扇贝等双壳类遗传多样性有些研究,但未见四角蛤蜊相关方面的报道。本文采用ISSR和RAPD两种分子标记方法对东港、庄河、皮口、烟台、青岛五个地理亚群四角蛤蜊的遗传多样性、种群遗传结构进行了研究,填补国内外在四角蛤蜊研究方面的空白。结果表明:RAPD比ISSR揭示了更高的遗传多样性。两者得到的群体遗传多样性指标Na、 Ne、H、I都较高,基因流水平也较高,群体间遗传分化指数GST〈0.5,这说明四角蛤蜊群体的遗传多样性丰富,但遗传多样性主要存在于亚群内,而不是亚群间,五个地理亚群显示出了较大的遗传相似性,这是由于基因流而造成的;通过计算五个亚群中任何两亚群之间的遗传多样性,发现任何组合的遗传多样性都很丰富,亚群之间的基因流水平也较高,遗传分化指数最大值仅为0.1461,同样说明了由于基因流的作用,亚群内的变异要远远大于亚群间的变异,而成为变异的主要方式。通过比较不同组合之间的各项指标还发现,基因流水平的高低、遗传相似性的程度和亚群之间的地理距离有关,地理位置离的越远的亚群,基因流水平越低,遗传分化指数越高,遗传相似系数越小;相反,地理距离越近的两亚群,基因流水平越高,遗传<WP=5>分化指数越小,遗传相似性就越大。通过ISSR和RAPD扩增反应得到的五个亚群间的遗传相似系数都很大,最小值为0.89,说明这五个亚群并没有因地理环境的差异而产生更大的分化。ISSR和RAPD得到的聚类分析图相似但不完全相同,虽然,两者都可以揭示辽宁的三个亚群亲缘关系近,山东的两个亚群亲缘关系近,但ISSR揭示,皮口和庄河在辽宁的三个亚群中的亲缘关系是最近,应该先聚到一起,而RAPD揭示东港和庄河的亲缘关系是最近的。ISSR和RAPD都揭示了在这五个亚群中,Pk亚群的遗传多样性最丰富,而Dg亚群的遗传多样性水平较低。更多还原

【Abstract】 Mactra veneriformis belongs to Mollusca, Lamellibranchia, Evlame vibranchia, Heterodata, Mactride. It is a kind of economic bivalves, which is normally restricted to the areas of the coasts in China. Some reports about the genetic diversity of some kinds of bivalves have been seen in some articles but have none about Mactra mactra. Random amplified polymorphic DNA (RAPD) analysis and Inter-simple sequence repeat (ISSR) were used to estimate genetic diversity and relationship in DNA of Mactramactra which belong to five districts, Dg, Pk, Zh, Yt, Qd. 27 RAPD primers and 16 ISSR primers were used to assess genetic variation and interrelationship among Mactramactra in these five districts. Among 27 RAPD primers, about 448 polymorphic genetic loci in 457 genetic loci were amplified, and among 16 ISSR primers, 234 polymorphic genetic loci in 240 loci were amplified. Some biological analysis softwares such as POPGEN were used to analysize the data. The results indicated that the level of genetic diversity examined by RAPD was higher than that by ISSR. The standard of genetic diversity investigated by these two molecular genetic <WP=59>markers such as Na, Ne, Ht, I were high. What’s more, the level of genetic flow was high. The coefficient of gene differentiation GST was lower than 0.5. These results revealed that the genetic diversity of these five populations was high, but mainly presented within populations not among populations. It was gene flow that led to high genetic identity among the five populations. The comparision made within the values revealed that gene flow and genetic identity remarkably related to the distance among these populations. The further the geographic distance between two populations was, the weaker was the gene flow, the higher was the GST, and the lower was the gentic identity. The genetic identity gained by RAPD and ISSR was high (the mix was 0.89), which indicated that these five populations did not differentiate into different populations under different enviroment, did belong to the same geographic strain. The dendrograms based on RAPD and ISSR data were similar but not the same. Although the results by RAPD and ISSR revealed that there was closely relationship among the three districts of Liaoning and also the two districts of Shandong. The result by ISSR showed that in the three districts of Liaoning, Pk was closely related to Zh and should be clustered firstly. On the contrary, RAPD indicated that Dg and Zh should be clustered firstly.ISSR and RAPD both indicated that genetic diversity of Pk in these five populations was highest, Dg’s was lowest.更多还原