Martin William F, Garg Sriram, Zimorski Verena
Institute for Molecular Evolution, Universität Düsseldorf, Universitätsstraße 1, Düsseldorf 40225, Germany
Institute for Molecular Evolution, Universität Düsseldorf, Universitätsstraße 1, Düsseldorf 40225, Germany.
Philos Trans R Soc Lond B Biol Sci. 2015 Sep 26;370(1678):20140330. doi: 10.1098/rstb.2014.0330.
For over 100 years, endosymbiotic theories have figured in thoughts about the differences between prokaryotic and eukaryotic cells. More than 20 different versions of endosymbiotic theory have been presented in the literature to explain the origin of eukaryotes and their mitochondria. Very few of those models account for eukaryotic anaerobes. The role of energy and the energetic constraints that prokaryotic cell organization placed on evolutionary innovation in cell history has recently come to bear on endosymbiotic theory. Only cells that possessed mitochondria had the bioenergetic means to attain eukaryotic cell complexity, which is why there are no true intermediates in the prokaryote-to-eukaryote transition. Current versions of endosymbiotic theory have it that the host was an archaeon (an archaebacterium), not a eukaryote. Hence the evolutionary history and biology of archaea increasingly comes to bear on eukaryotic origins, more than ever before. Here, we have compiled a survey of endosymbiotic theories for the origin of eukaryotes and mitochondria, and for the origin of the eukaryotic nucleus, summarizing the essentials of each and contrasting some of their predictions to the observations. A new aspect of endosymbiosis in eukaryote evolution comes into focus from these considerations: the host for the origin of plastids was a facultative anaerobe.
100多年来，内共生理论一直影响着人们对原核细胞和真核细胞差异的思考。文献中已经提出了20多种不同版本的内共生理论来解释真核生物及其线粒体的起源。其中很少有模型能解释真核厌氧菌。能量的作用以及原核细胞组织在细胞历史进化创新上所施加的能量限制，最近对内共生理论产生了影响。只有拥有线粒体的细胞才有生物能量手段来达到真核细胞的复杂性，这就是为什么在从原核生物到真核生物的转变过程中没有真正的中间过渡形式。当前版本的内共生理论认为宿主是古菌（一种古细菌），而不是真核生物。因此，古菌的进化历史和生物学对真核生物起源的影响比以往任何时候都更加显著。在这里，我们对内共生理论进行了综述，这些理论涉及真核生物和线粒体的起源以及真核细胞核的起源，总结了每个理论的要点，并将它们的一些预测与观察结果进行了对比。从这些思考中，真核生物进化中内共生的一个新方面成为焦点：质体起源的宿主是兼性厌氧菌。
