Buchheim M A, McAuley M A, Zimmer E A, Theriot E C, Chapman R L
Faculty of Biological Science, University of Tulsa, Oklahoma 74104-3189.
Mol Phylogenet Evol. 1994 Dec;3(4):322-43. doi: 10.1006/mpev.1994.1039.
Phylogenetic hypotheses generated from cladistic analysis of organismal and molecular data are shown to be generally congruent and/or complementary for comparisons of unicellular and colonial green algae in the Chlorophyceae. Cladistic analysis of organismal character data corroborates the alliance of colonial Stephanosphaera with unicellular Haematococcus (Haematococcaceae sensu Smith), inferred from previous studies of nuclear-encoded rRNA sequence data. The organismal data also support monophyly of the colonial Volvocaceae (sensu Smith). Alliances of other unicellular taxa, including those ascribed to the "Euchlamydomonas" Hauptgruppe (sensu Ettl), are not resolved by organismal characters principally because the structure of the data is skewed to shared ancestral characters (symplesiomorphies) and unique characters (autapomorphies) which define individual taxa only. Reanalysis of rRNA sequence data, with additional sequence data for critical taxa, does not support monophyly of the colonial Volvocaceae (sensu Smith). However, these data are weak in the support of the alternate hypothesis of nonmonophyly. In contrast, relationships among most unicellular flagellates are unambiguously resolved by the molecular data. Although the failure of the sequence data to resolve relationships among colonial flagellates appears to be due to a sampling of conservative sequences, an ancient, rapid radiation event or taxon sampling bias may also be contributing to the ambiguity problem. Results from analysis of a combined data set (organismal and molecular) are generally consistent with the inferences of the organismal character data regarding the colonial flagellates and are also consistent with the inferences of the sequence data regarding the unicellular taxa.
从生物体和分子数据的分支系统分析得出的系统发育假说表明，对于绿藻纲中单细胞和群体绿藻的比较，它们总体上是一致的和/或互补的。对生物体特征数据的分支系统分析证实了群体的Stephanosphaera与单细胞的Haematococcus（史密斯意义上的Haematococcaceae）的联盟，这是根据先前对核编码rRNA序列数据的研究推断出来的。生物体数据也支持群体的Volvocaceae（史密斯意义上的）的单系性。其他单细胞类群的联盟，包括那些归属于“Euchlamydomonas” Hauptgruppe（埃特尔意义上的）的类群，主要由于数据结构偏向于共享祖先特征（同塑特征）和仅定义单个类群的独特特征（自动衍征），而无法通过生物体特征得到解决。对rRNA序列数据进行重新分析，并增加关键类群的序列数据，并不支持群体的Volvocaceae（史密斯意义上的）的单系性。然而，这些数据对非单系性的替代假说的支持力度较弱。相比之下，可以通过分子数据明确解析大多数单细胞鞭毛虫之间的关系。尽管序列数据未能解析群体鞭毛虫之间的关系似乎是由于保守序列的采样问题，但一个古老的、快速的辐射事件或类群采样偏差也可能导致了这种模糊性问题。对组合数据集（生物体和分子）的分析结果总体上与关于群体鞭毛虫的生物体特征数据的推断一致，也与关于单细胞类群的序列数据的推断一致。
