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| 基于18S和ITS-5.8S rDNA基因序列的白色霞水母(Cyanea nozakii)的分子鉴定与检测 |
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李玉龙,董婧①,王彬,孙明,王爱勇,王文波
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辽宁省海洋水产科学研究院 辽宁省海洋生物资源与生态学重点实验室 大连 116023,辽宁省海洋水产科学研究院 辽宁省海洋生物资源与生态学重点实验室 大连 116023,辽宁省海洋水产科学研究院 辽宁省海洋生物资源与生态学重点实验室 大连 116023,辽宁省海洋水产科学研究院 辽宁省海洋生物资源与生态学重点实验室 大连 116023,辽宁省海洋水产科学研究院 辽宁省海洋生物资源与生态学重点实验室 大连 116023,辽宁省海洋水产科学研究院 辽宁省海洋生物资源与生态学重点实验室 大连 116023
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| 摘要: |
| 采用通用引物PCR扩增法,测定了辽东湾海域的白色霞水母(Cyanea nozakii)螅状体、碟状体及水母体的18S以及ITS-5.8S rDNA序列,同时利用GeneBank数据库中已有同源序列对其进行序列分析及系统分析。结果显示,白色霞水母3个个体的18S和ITS-5.8S rDNA序列完全一致。白色霞水母样品的ITS-5.8S rDNA序列与GenBank中未知真核生物的序列高度相似(≥99%),推测该物种可能是早期发育阶段(卵、浮浪幼虫或碟状体)的白色霞水母样品。霞水母属不同种间18S rDNA序列经比对后同源序列长度为1709bp,多态位点数33个;比对后ITS1同源序列长度为368bp,其中变异位点203个,简约信息位点数178个,单变异位点21个。基于18S rDNA基因序列的霞水母属种内和种间平均遗传距离分别为0、0.008,而基于ITS1序列的霞水母属种内和种间平均遗传距离分别为0.019、0.284。基于ITS1的种间遗传距离是种内遗传距离的15倍,适合于进行物种鉴定。NJ系统树的结果也表明同种的不同个体各自聚枝,其聚类结果大致与形态分类吻合。研究表明,ITS基因片段在霞水母不同种间变异较大,更适于大型水母种类鉴定、检测及属内种间水平的系统进化研究。 |
| 关键词: 白色霞水母 18S rDNA ITS-5.8S 分子鉴定 系统分析 |
| DOI：10.11693/hyhz20150200051 |
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| 基金项目:国家自然科学基金项目资助,31400406号;国家重点基础研究发展计划(973)项目,2011CB403601号;海洋公益性行业科研专项资助,201405010号。 |
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| MOLECULAR IDENTIFICATION AND DETECTION OF CYANEA NOZAKII BY PARTIAL SEQUENCING OF 18S RDNA AND ITS-5.8S |
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liyulong,dongjing,wangbin,sunming,wangaiyong and wangwenbo
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Liaoning Ocean and Fisheries Science research Institute,Liaoning Ocean and Fisheries Science research Institute,Liaoning Ocean and Fisheries Science research Institute,Liaoning Ocean and Fisheries Science research Institute,Liaoning Ocean and Fisheries Science research Institute,Liaoning Ocean and Fisheries Science research Institute
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| Abstract: |
| We determined partial sequences of nuclear 18S and ITS-5.8S rDNA from polyp, ephyra, and adult of jellyfish Cyanea nozakii, and compared them with available homologous sequences of other Cyanea jellyfish species in the GenBank in terms of sequence variation and genetic distance. Result shows that the nucleotide divergence in ITS-5.8S sequence was 0%-0.8% between C. nozakii and uncultured eukaryote species from the GenBank, suggesting that the uncultured eukaryote species was C. nozakii. In 18S rDNA, a 1709-bp homologous sequence was recognized at 33 variable sites in five Cyanea jellyfish species, while in ITS, a 368-bp long homologous sequence was shown including 203 variable sites, 178 parsimony informative sites, and 21 singleton sites. The average genetic distance inter-/intra-species was 0.008/0, and 0.284/0.019 in 18S rDNA and ITS1, respectively, showing that ITS1-based inter-species genetic distance was 15 times greater of inter-species one; and therefore the former is more suitable for species identification. Moreover, phylogenetic trees were constructed in the Neighbor-Joining method, from which different individuals of the same species grouped together. Therefore, the ITS1 gene fragments were highly diversified among different Cyanea species and could be applied to identify large-sized jellyfish and detect young jellyfish, and are helpful in molecular systematic studies at species or population level. |
| Key words: Cyanea nozakii 18S rDNA ITS-5.8S rDNA molecular identification phylogenetic analysis |