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Mitochondria are not captive bacteria

Harish, Ajith LU and Kurland, Charles G. LU (2017) In Journal of Theoretical Biology
Abstract

Lynn Sagan's conjecture (1967) that three of the fundamental organelles observed in eukaryote cells, specifically mitochondria, plastids and flagella were once free-living primitive (prokaryotic) cells was accepted after considerable opposition. Even though the idea was swiftly refuted for the specific case of origins of flagella in eukaryotes, the symbiosis model in general was accepted for decades as a realistic hypothesis to describe the endosymbiotic origins of eukaryotes. However, a systematic analysis of the origins of the mitochondrial proteome based on empirical genome evolution models now indicates that 97% of modern mitochondrial protein domains as well their homologues in bacteria and archaea were present in the universal... (More)

Lynn Sagan's conjecture (1967) that three of the fundamental organelles observed in eukaryote cells, specifically mitochondria, plastids and flagella were once free-living primitive (prokaryotic) cells was accepted after considerable opposition. Even though the idea was swiftly refuted for the specific case of origins of flagella in eukaryotes, the symbiosis model in general was accepted for decades as a realistic hypothesis to describe the endosymbiotic origins of eukaryotes. However, a systematic analysis of the origins of the mitochondrial proteome based on empirical genome evolution models now indicates that 97% of modern mitochondrial protein domains as well their homologues in bacteria and archaea were present in the universal common ancestor (UCA) of the modern tree of life (ToL). These protein domains are universal modular building blocks of modern genes and genomes, each of which is identified by a unique tertiary structure and a specific biochemical function as well as a characteristic sequence profile. Further, phylogeny reconstructed from genome-scale evolution models reveals that Eukaryotes and Akaryotes (archaea and bacteria) descend independently from UCA. That is to say, Eukaryotes and Akaryotes are both primordial lineages that evolved in parallel. Finally, there is no indication of massive inter-lineage exchange of coding sequences during the descent of the two lineages. Accordingly, we suggest that the evolution of the mitochondrial proteome was autogenic (endogenic) and not endosymbiotic (exogenic).

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epub
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Journal of Theoretical Biology
publisher
Academic Press
external identifiers
  • scopus:85026652443
  • wos:000413888500012
ISSN
0022-5193
DOI
10.1016/j.jtbi.2017.07.011
language
English
LU publication?
yes
id
dcc0c707-92e5-4987-a3c6-8f98ed3bebb2
date added to LUP
2017-08-31 14:48:18
date last changed
2018-01-16 13:24:18
@article{dcc0c707-92e5-4987-a3c6-8f98ed3bebb2,
  abstract     = {<p>Lynn Sagan's conjecture (1967) that three of the fundamental organelles observed in eukaryote cells, specifically mitochondria, plastids and flagella were once free-living primitive (prokaryotic) cells was accepted after considerable opposition. Even though the idea was swiftly refuted for the specific case of origins of flagella in eukaryotes, the symbiosis model in general was accepted for decades as a realistic hypothesis to describe the endosymbiotic origins of eukaryotes. However, a systematic analysis of the origins of the mitochondrial proteome based on empirical genome evolution models now indicates that 97% of modern mitochondrial protein domains as well their homologues in bacteria and archaea were present in the universal common ancestor (UCA) of the modern tree of life (ToL). These protein domains are universal modular building blocks of modern genes and genomes, each of which is identified by a unique tertiary structure and a specific biochemical function as well as a characteristic sequence profile. Further, phylogeny reconstructed from genome-scale evolution models reveals that Eukaryotes and Akaryotes (archaea and bacteria) descend independently from UCA. That is to say, Eukaryotes and Akaryotes are both primordial lineages that evolved in parallel. Finally, there is no indication of massive inter-lineage exchange of coding sequences during the descent of the two lineages. Accordingly, we suggest that the evolution of the mitochondrial proteome was autogenic (endogenic) and not endosymbiotic (exogenic).</p>},
  author       = {Harish, Ajith and Kurland, Charles G.},
  issn         = {0022-5193},
  language     = {eng},
  month        = {07},
  publisher    = {Academic Press},
  series       = {Journal of Theoretical Biology},
  title        = {Mitochondria are not captive bacteria},
  url          = {http://dx.doi.org/10.1016/j.jtbi.2017.07.011},
  year         = {2017},
}