Phylogenetic analysis of "Volvocacae" for comparative genetic studies
Phylogenetic analysis of "Volvocacae" for comparative genetic studies
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DOI：
10.1073/pnas.96.24.13892
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发表时间：
1999-11-23
影响因子：
11.1
通讯作者：
Coleman, AW
中科院分区：
文献类型：
--
作者：
Coleman, AW
基于代表经典沃尔沃科的基本上所有属和种的多个分离株的序列分析已经阐明了它们的系统发育关系。克隆的内部转录间隔序列（ITS-1.和ITS-2，位于核核糖体基因顺反子的5.8S基因侧翼）进行比对，由ITS转录物二级结构特征引导，并进行简约性和邻近连接距离分析。结果证实了单一共同祖先的概念，并且在所有已测序的绿色单细胞中，莱茵衣藻最为相似。在所有情况下，杂交分离株都是进化树上最近的邻居。通过序列比较，一些分类单元，无论处于什么水平，都被证明是进化枝，但其他分类单元则提供了惊人的例外。形态学上的 Pandorina morum 物种分布广泛且交配对多样，被发现涵盖了四种 Volvulina 的所有分离株。 Platydorina 似乎起源较早，并不属于 Eudorina 属，有时会因形态而与 Eudorina 混淆。 Pleodorina 的四种物种似乎与 Eudorina 的例子有不同的关联。尽管团藻属各有进化枝，但团藻属却不是。结论证实并扩展了先前对核 SSU 和 LSU rDNA 基因以及质体编码的 rbcL 和 atpB 的、更有限的研究。系统发育树表明哪些经典分类特征最具误导性，并为细胞周期相关和其他改变的分子研究提供了框架，这些改变在这个经典家族中产生了营养和有性群体模式的多样性。
Sequence analysis based on multiple isolates representing essentially all genera and species of the classic family Volvocaeae has clarified their phylogenetic relationships. Cloned internal transcribed spacer sequences (ITS-1. and ITS-2, flanking the 5.8S gene of the nuclear ribosomal gene cistrons) were aligned, guided by ITS transcript secondary structural features, and subjected to parsimony and neighbor joining distance analysis. Results confirm the notion of a single common ancestor, and Chlamydomonas reinharditii alone among all sequenced green unicells is most similar. interbreeding isolates were nearest neighbors on the evolutionary tree in all cases. Some taxa, at whatever level, prove to be clades by sequence comparisons, but others provide striking exceptions. The morphological species Pandorina morum, known to be widespread and diverse in mating pairs, was found to encompass all of the isolates of the four species of Volvulina. Platydorina appears to have originated early and not to fall within the genus Eudorina, with which it can sometimes be confused by morphology. The four species of Pleodorina appear variously associated with Eudorina examples. Although the species of Volvox are each clades, the genus Volvox is not The conclusions confirm and extend prior, more limited, studies on nuclear SSU and LSU rDNA genes and plastid-encoded rbcL and atpB. The phylogenetic tree suggests which classical taxonomic characters are most misleading and provides a framework for molecular studies of the cell cycle-related and other alterations that have engendered diversity in both vegetative and sexual colony patterns in this classical family.