When trying to reconstruct the evolutionary trajectories during early eukaryogenesis, one is struck by clear differences in the developments of two organelles of endosymbiotic origin: the mitochondrion and the chloroplast. From a symbiogenic perspective, eukaryotic development can be interpreted as a process in which many of the defining eukaryotic characteristics arose as a result of mutual adaptions of both prokaryotes (an archaeon and a bacterium) involved. This implies that many steps during the bacterium-to-mitochondrion transition trajectory occurred in an intense period of dramatic and rapid changes. In contrast, the subsequent cyanobacterium-to-chloroplast development in a specific eukaryotic subgroup, leading to the photosynthetic lineages, occurred in a full-fledged eukaryote. The commonalities and differences in the two trajectories shed an interesting light on early, and ongoing, eukaryotic evolutionary driving forces, especially endogenous reactive oxygen species (ROS) formation. Differences between organellar ribosomes, changes to the electron transport chain (ETC) components, and mitochondrial codon reassignments in nonplant mitochondria can be understood when mitochondrial ROS formation, e.g., during high energy consumption in heterotrophs, is taken into account.

中文翻译：

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根据内部ROS的挑战比较线粒体和叶绿体的早期真核整合：时机至关重要。

当试图重建真核生物早期的进化轨迹时，内共生起源的两个细胞器线粒体和叶绿体的明显差异给人留下了深刻的印象。从共生的角度来看，真核生物的发展可以解释为一个过程，其中由于两个原核生物（古细菌和细菌）的相互适应而产生了许多定义性的真核生物特征。这意味着在细菌向线粒体过渡的过程中，许多步骤发生在剧烈而迅速的变化的强烈时期。相反，在特定的真核生物亚组中，随后的蓝细菌到叶绿体的发育，导致了光合谱系，发生在成熟的真核生物中。两条轨迹的共性和差异为早期和持续的真核生物进化驱动力，特别是内源性活性氧（ROS）的形成提供了有趣的启示。当考虑到线粒体ROS的形成（例如在异养生物中的高能量消耗期间）时，可以理解细胞器核糖体之间的差异，电子传递链（ETC）组件的变化以及线粒体密码子在非植物线粒体中的重分配。