Late acquisition of mitochondria by a host with chimaeric prokaryotic ancestry

摘要: Evidence that among the eukaryotic ancestor genes, those derived from proto-mitochondrion have closest evolutionary distances to their bacterial relatives. The eukaryote cell is so much larger and more complex than cells of bacteria archaea it hard recreate steps whereby evolved. One current view evolution eukaryotes was triggered when an archaea-like accommodated went on become mitochondria. An alternative were well way modern form before they acquired became This second supported by a study Alexandros Pittis Toni Gabaldon showing mitochondrial genes are closely similar supposed relations many other own inferred prokaryote cousins. result, which challenges views, suggests mitochondria late additions already evolving. origin stands as major conundrum in biology1. Current evidence indicates last common possessed hallmarks, including subcellular organization1,2,3. In addition, lack intermediates elucidation relative order emergence traits. Mitochondria ubiquitous organelles alphaproteobacterial endosymbiont4. Different hypotheses disagree whether early or during eukaryogenesis5. Similarly, nature complexity receiving host debated, with models ranging simple prokaryotic proto-eukaryote1,3,6,7. Most competing scenarios can be roughly grouped into either mito-early, consider driving force eukaryogenesis endosymbiosis host, mito-late, postulate significant predated endosymbiosis3. Here we provide for endosymbiosis. We use phylogenomics directly test proto-mitochondrial proteins earlier later ancestor. find protein families ancestry localization show shortest phylogenetic relatives, compared different cellular localization. Altogether, our results shed new light long-standing question compelling support acquisition had proteome chimaeric origin. argue one ultimate provided definitive selective advantage mitochondria-bearing over less forms.