The Origin and Diversification of Mitochondria.
Level 5 - mechanism / opinion, no new human data
Narrative review of evolutionary theory and comparative biology (Level 5 by design analogy)
PubMed 29112874 · doi:10.1016/j.cub.2017.09.015
What was done
Narrative review synthesizing evidence and evolutionary models regarding the origin of mitochondria from an alphaproteobacterial endosymbiont integrated into an Asgard Archaea-related host, and its subsequent diversification across eukaryotes.
What was found
No quantitative data are reported in the abstract. The review details the sequence of evolutionary events necessary for organelle transition, including the emergence of hundreds of new genes, development of a protein import system, insertion of membrane transporters, genome reduction, endosymbiotic gene transfer, and protein retargeting. It notes ongoing controversy regarding the nature of the original endosymbiont, initial host interactions, and the timing of integration relative to other eukaryotic features.
Why it matters
Clarifies the evolutionary trajectory of eukaryotic cell complexity by synthesizing how endosymbiosis transformed a free-living bacterium into a specialized, structurally integrated organelle.
Limits
Narrative review containing no original empirical or quantitative measurements. The exact identity of the ancestral endosymbiont and the chronology of integration events remain debated.
Cited by
- context Mitochondria originated roughly 1.5 billion years ago via endosymbiosis between two distinct types of bacteria.