Department of Medical Biochemistry, AmsterdamUMC, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands.
Bioessays. 2020 Apr;42(4):e1900157. doi: 10.1002/bies.201900157. Epub 2020 Feb 20.
Eukaryotic origins are heavily debated. The author as well as others have proposed that they are inextricably linked with the arrival of a pre-mitochondrion of alphaproteobacterial-like ancestry, in a so-called symbiogenic scenario. The ensuing mutual adaptation of archaeal host and endosymbiont seems to have been a defining influence during the processes leading to the last eukaryotic common ancestor. An unresolved question in this scenario deals with the means by which the bacterium ends up inside. Older hypotheses revolve around the application of known antagonistic interactions, the bacterium being prey or parasite. Here, in reviewing the field, the author argues that such models share flaws, hence making them less likely, and that a "pre-symbiotic stage" would have eased ongoing metabolic integration. Based on this the author will speculate about the nature of the (endo) symbiosis that started eukaryotic evolution-in the context of bacterial entry being a relatively "early" event-and stress the differences between this uptake and subsequent ones. He will also briefly discuss how the mutual adaptation following the merger progressed and how many eukaryotic hallmarks can be understood in light of coadaptation. Also see the video abstract here https://youtu.be/ekqtNleVJpU.
真核生物的起源存在很大争议。作者以及其他一些人提出，真核生物与具有α变形菌样祖先的前线粒体的出现有着千丝万缕的联系，这被称为共生起源假说。随后，古菌宿主和内共生体之间的相互适应似乎在导致最后一个真核生物共同祖先的过程中产生了决定性的影响。在这种情况下，一个悬而未决的问题是细菌最终是如何进入内部的。早期的假设涉及到应用已知的拮抗相互作用，即细菌是猎物还是寄生虫。在这里，作者在回顾该领域时认为，这些模型存在缺陷，因此不太可能，而“共生前阶段”将有助于持续的代谢整合。基于这一点，作者将推测在细菌进入相对“早期”事件的情况下，启动真核生物进化的（内）共生的性质，并强调这种摄取与随后的摄取之间的差异。他还将简要讨论合并后共同适应是如何发展的，以及根据共同适应可以理解多少真核生物的特征。也可以在此处查看视频摘要：https://youtu.be/ekqtNleVJpU。
