Proto-mitochondrion

Proto-mitochondrion
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Alpha Proteobacteria

The proto-mitochondrion is the ancestral bacterial endosymbiont from which all mitochondria are thought to be derived.

Phylogeny

The phylogenetic analyses of the few genes that are still encoded in the genomes of modern mitochondria suggest an alpha-proteobacterial origin for this endosymbiont. Although the order Rickettsiales has been proposed as the alpha-proteobacterial sister-group of mitochondria, there is no definitive evidence as to from which alpha-proteobacterial group the proto-mitochondrion emerged.

Phylogeny of Rickettsiales
Magnetococcidae
Magnetococcales
Magnetococcaceae

Magnetococcus marinus
Caulobacteridae

Rhodospirillales, Sphingomonadales, Rhodobacteraceae, Rhizobiales, etc.

Holosporales



Rickettsidae
Pelagibacterales
Pelagibacteraceae

Pelagibacter

subgroups Ib, II, IIIa, IIIb, IV and V

Proto-mitochondria
Anaplasmataceae



Ehrlichia

Anaplasma

Wolbachia

Neorickettsia
Midichloriaceae

Midichloria



Rickettsiaceae

Rickettsia








Robust 16S + 23S phylogeny of Rickettsidae from Ferla et al. (2013)[1]

Metabolism

Toni Gabaldón and Martijn Huynen (2003) reconstructed the proteome (the entire set of proteins expressed by a genome) and corresponding metabolism of the proto-mitochondrion by comparing extant alpha-proteobacterial and eukaryotic genomes. They concluded that this organism was an aerobic alpha-proteobacterium catabolyzing lipids, glycerol and other compounds provided by the host. At least 630 gene families derived from this organism can still be found in the 9 eukaryotic genomes analyzed in the study.[2]

See also

References

  1. ↑ Ferla, M. P.; Thrash, J. C.; Giovannoni, S. J.; Patrick, W. M. (2013). "New rRNA gene-based phylogenies of the Alphaproteobacteria provide perspective on major groups, mitochondrial ancestry and phylogenetic instability". PLoS ONE. 8 (12): e83383. doi:10.1371/journal.pone.0083383. PMC 3859672Freely accessible. PMID 24349502.
  2. ↑ Gabaldón, T.; et al. (2003). "The proto-mitochondrial metabolism". Science. 301 (5633): 690. doi:10.1126/science.1085463. PMID 12893934.


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