Eschbach S, Wolters J, Sitte P
Institut für Biologie II, Zellbiologie, Universität Freiburg, FRG.
J Mol Evol. 1991 Mar;32(3):247-52. doi: 10.1007/BF02342747.
The cryptomonad Pyrenomonas salina presumably has arisen from a symbiotic event involving a flagellated phagotrophic host cell and a photosynthetic eukaryote as the symbiont. Correspondingly, in this unicellular alga there are four different genomes, e.g., the nuclear and the mitochondrial genomes of the host cell as well as the plastid genome and the genome contained in the vestigial nucleus of the endocytobiont (nucleomorph). To analyze the origin of one of the symbiotic partners the small subunit rRNA gene sequence of the host cell nucleus was determined, and a secondary structure model has been constructed. This sequence is compared to those of 40 other eukaryotes. A phylogenetic tree constructed using the neighborliness method revealed a close relationship between the host cell of P. salina and the chlorophytes, whereas the rhodophytes diverge more deeply in the tree.
隐滴虫盐生梨甲藻大概起源于一个共生事件，该事件涉及一个具鞭毛的吞噬营养宿主细胞和一个作为共生体的光合真核生物。相应地，在这种单细胞藻类中有四种不同的基因组，例如宿主细胞的核基因组和线粒体基因组，以及质体基因组和内共生体（核质体）残余核中所含的基因组。为了分析其中一个共生伙伴的起源，测定了宿主细胞核的小亚基rRNA基因序列，并构建了二级结构模型。将该序列与其他40种真核生物的序列进行了比较。使用邻接法构建的系统发育树显示，盐生梨甲藻的宿主细胞与绿藻之间关系密切，而红藻在树中分歧更深。
