Informative characteristics of 12 divergent domains in complete large subunit rDNA sequences from the harmful dinoflagellate genus, Alexandrium (Dinophyceae)
Informative characteristics of 12 divergent domains in complete large subunit rDNA sequences from the harmful dinoflagellate genus, Alexandrium (Dinophyceae)
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DOI：
10.1111/j.1550-7408.2007.00251.x
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发表时间：
2007-03-01
影响因子：
2.2
通讯作者：
Han, Myung-Soo
中科院分区：
文献类型：
--
作者：
Ki, Jang-Seu;Han, Myung-Soo
亚历山大藻属包括感兴趣的生物，用于研究甲藻的进化及其作为有毒藻类影响人类健康和渔业的影响。虽然亚历山大藻和其他甲藻的rDNA序列包含了大量的遗传信息，但只有部分的大亚基（LSU）rDNA序列可用。在这里，我们报告完整的LSU rDNA序列从11株亚历山大，包括亚历山大affine，亚历山大catenella，亚历山大fundyense，亚历山大minutum，和亚历山大tamarense，并讨论其分段结构域和结构。据记录，推定的LSU rRNA编码区长约3，400 bp。与其他生物相比，它们的GC含量（约43.7%）是最低的。此外，没有AT丰富的区域中发现亚历山大LSU rDNA，虽然低GC含量记录内的LSU rDNA。LSU rDNA二级结构和简约性分析表明，LSU rDNA的变异主要集中在D区，其中D2区的信息量最大。这种高D结构域的变异性可以使不同的亚历山大属的成员在物种水平上进行分类。此外，系统发育分析的蜂窝组使用完整的LSU序列强烈支持以前的研究结果，甲藻和apicomplexans形成一个分支。
The genus Alexandrium includes organisms of interest, both for the study of dinoflagellate evolution and for their impacts as toxic algae affecting human health and fisheries. Only partial large subunit (LSU) rDNA sequences of Alexandrium and other dinoflagellates are available, although they contain much genetic information. Here, we report complete LSU rDNA sequences from 11 strains of Alexandrium, including Alexandrium affine, Alexandrium catenella, Alexandrium fundyense, Alexandrium minutum, and Alexandrium tamarense, and discuss their segmented domains and structure. Putative LSU rRNA coding regions were recorded to be around 3,400bp long. Their GC content (about 43.7%) is among the lowest when compared with other organisms. Furthermore, no AT-rich regions were found in Alexandrium LSU rDNA, although a low GC content was recorded within the LSU rDNA. No intron-like sequences were found. The secondary structure of the LSU rDNA and parsimony analyses showed that most variation in LSU rDNA is found in the divergent (D) domains with the D2 region being the most informative. This high D domain variability can allow members of the diverse Alexandrium genus to be categorized at the species level. In addition, phylogenetic analysis of the alveolate group using the complete LSU sequences strongly supported previous findings that the dinoflagellates and apicomplexans form a clade.