Gray M W, Sankoff D, Cedergren R J
Nucleic Acids Res. 1984 Jul 25;12(14):5837-52. doi: 10.1093/nar/12.14.5837.
To probe the earliest evolutionary events attending the origin of the five known genome types (archaebacterial, eubacterial, nuclear, mitochondrial and plastid), we have analyzed sequences corresponding to a ubiquitous, highly conserved core of secondary structure in small subunit rRNA. Our results support (i) the existence of three primary lineages (archaebacterial, eubacterial, and nuclear), (ii) a specific eubacterial ancestry for plastids and mitochondria (plant, animal, fungal), and (iii) an endosymbiotic, evolutionary origin of the two types of organelle from within distinct groups of eubacteria (blue-green algae (cyanobacteria) in the case of plastids, nonphotosynthetic aerobic bacteria in the case of mitochondria). In addition, our analysis suggests (iv) a biphyletic origin of mitochondria, with animal and fungal mitochondria branching together but separately from plant mitochondria, and (v) a monophyletic origin of plastids. The method described here provides a powerful and generally applicable molecular taxonomic approach towards a global phylogeny encompassing all organisms and organelles.
为了探究与五种已知基因组类型（古细菌、真细菌、细胞核、线粒体和质体）起源相关的最早进化事件，我们分析了与小亚基核糖体RNA二级结构中一个普遍存在、高度保守的核心相对应的序列。我们的结果支持：（i）存在三个主要谱系（古细菌、真细菌和细胞核）；（ii）质体和线粒体（植物、动物、真菌）具有特定的真细菌祖先；（iii）这两种细胞器是从不同的真细菌群体内通过内共生方式进化而来（质体起源于蓝藻（蓝细菌），线粒体起源于非光合需氧细菌）。此外，我们的分析表明：（iv）线粒体有双源起源，动物和真菌的线粒体一起分支，但与植物线粒体分开；（v）质体有单源起源。这里描述的方法为构建涵盖所有生物和细胞器的全球系统发育提供了一种强大且普遍适用的分子分类学方法。
