| 摘要: |
| 采用分子生物学方法,进行了江苏和广西两个地区不同花纹文蛤群体的核糖体DNA转录间隔区(ITS2)的序列分析研究。结果表明,广西的文蛤群体和江苏的群体相比较,仅发现江苏群体在333—336bp处发生了缺失,江苏群体内不同花纹文蛤个体间的ITS2也发生了变化。聚类分析结果证实了序列分析结果,广西文蛤群体和江苏文蛤群体间发生了遗传变异,江苏文蛤群体内部也发生了遗传分化。 |
| 关键词: 文蛤,花纹,ITS2 |
| DOI： |
| 分类号: |
| 基金项目:国家海洋863项目“文蛤大规模人工育苗技术”,2002-AA-603014号;宁波市科技局重点项目,2004C100055号 |
|
| THE ANALYSIS OF ITS2 IN MERETRIX MERETRIX WITH DIFFERENT STRIPES |
|
LI Tai-Wu1, ZHANG An-Guo1, SU Xiu-Rong1, LI Cheng-Hua2,3, LIU Bao-Zhong2, LIN Zhi-Hua4, CHAI Xue-Liang4
|
|
1.Faculty of Life Science and Biotechnology, Ningbo University, Ningbo, 315211;2.Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071;3.Graduate School, Chinese Academy of Sciences, Beijing, 100039;4.Zhejiang Mariculture Research Institute, Wenzhou, 325005
|
| Abstract: |
| The orient clam Meretrix meretrix Linnaeus is one o f the common species along the coast of eastern countries such as Japan, Korea and China. It is distributed extensively all over the coast of China as one of the most important aquaculture species, and featured with special stripes on the shell of most of the mollusca. However, the stripes are different in species, dense and colorful in the species from Bohai Sea and Yellow Sea, but loose and simple for those from South China Sea and East China Sea. The juvenile ones in Zhejiang coast have clear stripes that came from Shandong coast, but no significant stripe was found if the juvenile came from Jiangsu coast. In order to illustrate the distinctness of the different striped clams, we collected samples in Jiangsu and Guangxi coasts in October 2003. Those samples were classified in to 5 groups in stripe color and pattern.
The internal transcribed spacer (ITS), a portion of the nuclear rDNA cistron, conventionally includes the entire ITS1, 518S gene and ITS2. The ITS1 and ITS2 are relatively fast evolving sequences. Furthermore, the ITS2 lies between the 5.8S and 28S RNA genes in typical length 200–400bp, and is easily amplified by polymerase chain reactions (PCR) informative at intraspecific and interspecific level. Therefore, the ITS2 of Meretrix meretrixof Jiangsu and Guangxi populations were amplified, sequenced, aligned and phylogenetically analyzed. The results of sequences alignment showed that the alignment is 473bp long. The Jiangsu population had few deletions at site 333–336bp and other sites compared with the Guangxi population. The phylogenetic tree shows the genetic relationship among these populations, and demonstrates the progress of the systematic evolution of the species. The results indicated that the yellow one in Jiangsu population had a closer relationship with the species in Guangxi population. We proposed that the differences in the sequences of ITS2 may be resulted from the variation in individual clams. In view of the geographical distribution, the populations in Guangxi and Jiangsu are far from each other. They are difficult to interchange with each other genetically. The environmental conditions such as the climate and seawater composition are greatly different in the two localities. Therefore, after the long-term natural selection, it is inevitable that the genetic variation would occur in some individual clams in the two populations. Generally speaking, the greater the geographic distance between two populations, the bigger the genetic distance. |
| Key words: Meretrix meretrix, Stripe, ITS2 |
