| 摘要: |
| 利用fAFLP 标记技术和PCR-RFLP 技术, 对采集于广西的形态和壳色变异很大的2 个文蛤群体(G、W)以及山东文蛤(S)群体进行了遗传结构和亲缘关系研究。fAFLP 分析显示：在457 个总扩增位点中存在53 个W 群体的特异性位点(其中9 个为100%显性)、21 个G 群体的特异性位点、14 个S 群体的特异性位点, 这些位点可作为群体鉴别的特征性标记; 通过计算群体间相对遗传距离和聚类分析, 发现S 和G 间的遗传距离最小(0.0424), 在系统树上首先聚在一起, 而W 与S、G 的相对遗传距离均很大(0.2308 和0.2305), 单独分出一支。对文蛤核糖体ITS 的PCR-RFLP 结果显示: W的三个不同壳色类群(WX、WC、WH)的酶切结果完全一致, 而与G 和S 群体差别较大; G 和S 群体基本一致, 但也稍有差别。进一步的ITS 序列分析显示: W 的ITS 序列长度为1266—1269bp, 而G和S 分别为1614bp 和1520bp; W 群体内部序列比较保守, 而与G 和S 群体之间在ITS1 和ITS2 开始和结尾处均存在多处插入/缺失; 在依据序列构建的系统树上, WX、WC、WH 三个类群聚在一起, S和G 聚为另一支, 两支相距甚远。本研究结果表明, fAFLP 标记分析、PCR-RFLP 分析和ITS 序列分析结果一致, W 群体和G、S 群体的差异较大, 已超出种内群体间的遗传变异, S 和G 尽管存在遗传分化, 但仍应同属Meretrix meretrix 一个物种。
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| 关键词: 文蛤, fAFLP, ITS, PCR-RFLP, 遗传结构, 亲缘关系 |
| DOI：10.11693/hyhz200901006006 |
| 分类号: |
| 基金项目:国家高技术研究发展计划(863 计划)资助项目, 2006AA10A410 号; 浙江省科技厅重大科技攻关计划资助项目, 2006C12013 号;国家科技基础条件平台建设计划资助项目, 2007DKA30470-015 号 |
附件 |
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| ANALYSIS OF MERETRIX CLAMS FROM GUANGXI BASED ON fAFLP MARKERS AND ITS SEQUENCES |
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LIN Zhi-Hua1,2, HUANG Xiao-Ting3, DONG Ying-Hui1, BAO Zhen-Min3, HU Jing-Jie3
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1.Zhejiang Wanli University;2.Zhejiang Mariculture Research Institute;3.Ocean University of China
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| Abstract: |
| The taxonomy of genus Meretrix has been in argument over several discrepancies among scientists in the world for a long while. Two groups of Meretrix clam (G & W) existed much variance on shell shape, color and pattern were collected from Beihai, Guangxi Province. One kind of Meretrix clam (G) is similar in shell color and pattern to Meretrix meretrix widely distributed in China costal region, another (W) is white color and convex in shell width. Genetic relationship between G and W was addressed by the fAFLP and PCR-RFLP compared with that of Shandong population of M. meretrix. The results of fAFLP analysis showed that each group had their own specific bands (loci) in which there were 53 unique loci in Group W, 21 unique loci in Group G, and 14 unique loci in S group. These unique loci could be taken for molecular markers to classify and distinguish other groups. The genetic distance matrix between Groups S and G was 0.0424, but the genetic distance matrix of W group between population S or G were 0.2308 or 0.2305 in respectively. The phylogenetic trees by the methods of Neibour-Joining (NJ) indicated that Groups S and G were more closely related, but Group W was much independently clustered among groups. The result of PCR-RFLP suggested that W group was different from Groups G and S. The internal transcribed spacer (ITS) region was sequenced. The results show that the size of ITS ranged 1266—1269bp in W group, and 1614bp in Group G and 1520bp in S group. The sequences of W group were conserved, but obviously different from Groups G and. Phylogenetic trees by NJ method showed that Group G was more closely related to Group S, but Group W was much independent cluster. The results fully reveal that Group G belongs to M. meretrix, and Group W is an independent species. But we still could not classify Group W to M. lusoria or M. larmarckii, even a new species of genus Meretrix. More researches shall be carried out in the future.
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| Key words: Meretrix, fAFLP, ITS, PCR-RFLP, Genetic structure, Genetic relationship |
