Lang B F, Gray M W, Burger G
Canadian Institute for Advanced Research, Département de Biochimie, Université de Montréal, Canada.
Annu Rev Genet. 1999;33:351-97. doi: 10.1146/annurev.genet.33.1.351.
Recent results from ancestral (minimally derived) protists testify to the tremendous diversity of the mitochondrial genome in various eukaryotic lineages, but also reinforce the view that mitochondria, descendants of an endosymbiotic alpha-Proteobacterium, arose only once in evolution. The serial endosymbiosis theory, currently the most popular hypothesis to explain the origin of mitochondria, postulates the capture of an alpha-proteobacterial endosymbiont by a nucleus-containing eukaryotic host resembling extant amitochondriate protists. New sequence data have challenged this scenario, instead raising the possibility that the origin of the mitochondrion was coincident with, and contributed substantially to, the origin of the nuclear genome of the eukaryotic cell. Defining more precisely the alpha-proteobacterial ancestry of the mitochondrial genome, and the contribution of the endosymbiotic event to the nuclear genome, will be essential for a full understanding of the origin and evolution of the eukaryotic cell as a whole.
来自原始（最少衍生）原生生物的最新研究结果证明了线粒体基因组在各种真核生物谱系中的巨大多样性，但也强化了这样一种观点，即作为内共生α-变形菌后代的线粒体在进化过程中只出现过一次。连续内共生理论是目前解释线粒体起源最流行的假说，它假定一个含有细胞核的真核宿主捕获了一个α-变形菌内共生体，这个宿主类似于现存的无线粒体原生生物。新的序列数据对这一设想提出了挑战，反而增加了线粒体起源与真核细胞核基因组起源同时发生并对其产生重大贡献的可能性。更精确地界定线粒体基因组的α-变形菌祖先以及内共生事件对核基因组的贡献，对于全面理解真核细胞整体的起源和进化至关重要。
