What it is
Mitochondria arose about 2 billion years ago from the endosymbiosis of a bacterium with an archaea-related host cell. To trace their origins and evolution, the authors compared experimentally defined mitochondrial proteomes (mitoproteomes) of eight organisms from the MitoCarta Tree of Life project, identifying 8,619 distinct mitochondrial proteins in 3,199 families, 43% of which lack Pfam domains. They then retrained a classifier based on a protein language model on these experimental mitoproteomes to predict the mitoproteomes of about 200 eukaryotes, used the expanded set to trace mitochondrial evolution, and finally reconstructed the mitoproteome of the last eukaryotic common ancestor (LECA).
Why it matters
The comparison turns up 33 protein families that are conserved in eukaryotic pathogens yet absent in humans, which the authors present as promising candidate targets for protozoan infectious diseases. Across the expanded set, mitochondria follow very different evolutionary trajectories, from clade-specific expansions of gene families to extreme reductions of the mitoproteome that seem to be on the way to losing the organelle entirely. The reconstruction indicates that LECA already possessed a complex mitochondrion capable of both aerobic and anaerobic metabolism.
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Filed underMitochondrial Function and Pathology, Protist diversity and phylogeny, Genomics and Phylogenetic Studies
