PHYLOGENY OF THE COLONIAL GREEN FLAGELLATES - A STUDY OF 18S AND 26S RIBOSOMAL-RNA SEQUENCE DATA
PHYLOGENY OF THE COLONIAL GREEN FLAGELLATES - A STUDY OF 18S AND 26S RIBOSOMAL-RNA SEQUENCE DATA
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DOI：
10.1016/0303-2647(91)90015-d
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发表时间：
1991-01-01
期刊：
影响因子：
1.6
通讯作者：
CHAPMAN, RL
中科院分区：
文献类型：
--
作者：
BUCHHEIM, MA;CHAPMAN, RL
基于核18S和26S rRNA序列数据的群体绿藻鞭毛虫系统发育关系研究表明，群体习性至少有两个独立的起源。除Stephanosphaera外，所有的群落类群均与莱茵衣藻（Chlamydomonas reinhardtii）和其他被Ettl归为真衣藻类群的衣藻类群归为一类。相反，Stephanosphaera与其他单细胞鞭毛虫（包括Haematococcus）结盟。对比18S和26S的数据可以发现，经过分类分析，两组数据得出了不同的结果。18S的数据提供了支持更基础的分化的主要信号，但是这些数据并没有明确地解决包括大多数殖民地鞭毛虫和代表真衣藻群的衣藻类群在内的分支中各类群之间的关系。相比之下，26S数据比18S数据具有更少的支持基础分化的信息位点，但在对18S和26S rRNA序列数据的综合分析中，26S数据提供了许多支持群体鞭毛虫分支分类群解析的信号。来自26S分子和其他分类群的额外序列数据可能会减少从群落鞭毛虫序列数据推断的拓扑模糊性。或者，殖民地谱系中分类群的古老和快速辐射可以解释拓扑模糊性。尽管存在一些尚未解决的关系问题，但对组合数据集的分支分析为这些鞭毛虫的进化概念提供了一些强有力的支持。
A study of phylogenetic relationships of the colonial green algal flagellates based on nuclear 18S and 26S rRNA sequence data suggests that the colonial habit has had at least two independent origins. All colonial taxa included in the analysis, except Stephanosphaera, are allied in a clad with Chlamydomonas reinhardtii and other Chlamydomonas taxa ascribed to the Euchlamydomonas group by Ettl. In contrast, Stephanosphaera is allied with other unicellular flagellates including Haematococcus. Comparison of the 18S and 26S data shows that the two sets of data yield different results following cladistic analysis. The 18S data provide the principal signal that supports the more basal divergences, but the data do not unambiguously address relationships among taxa in the clade that includes most colonial flagellates and Chlamydomonas taxa representative of the Euchlamydomonas group (sensu Ettl). In contrast, the 26S data have fewer informative sites that support basal divergences than the 18S data, but provide much of the signal that supports resolution of taxa in the colonial flagellate clade in an analysis of the combined 18S and 26S rRNA sequence data. Additional sequence data from the 26S molecule and additional taxa may reduce the topological ambiguity inferred from the sequence data for the colonial flagellates. Alternatively, an ancient and rapid radiation of taxa in the colonial lineage could account for the topological ambiguity. Despite some unresolved questions of relationships, cladistic analysis of the combined data sets provides some robustly supported concepts of evolution in these flagellates.