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Isolation and Functional Analysis of Mitochondria from Cultured Cells and Mouse Tissue
Published on: March 23, 2015
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Mitochondria are not captive bacteria
Ajith Harish1, Charles G Kurland2
1Department of Cell and Molecular Biology, Section of Structural and Molecular Biology, Uppsala University, Uppsala, Sweden.
Journal of Theoretical Biology
|July 30, 2017
Summary
Mitochondrial evolution was likely autogenic, not endosymbiotic. Analysis shows most mitochondrial protein domains existed in the universal common ancestor, suggesting parallel evolution of eukaryotes and prokaryotes.
Area of Science:
- Cell biology
- Evolutionary biology
- Genomics
Background:
- The endosymbiotic theory proposed mitochondria originated from free-living prokaryotes.
- This theory has been widely accepted for decades to explain eukaryotic cell origins.
- Previous models focused on specific organelles, like flagella, which were refuted.
Purpose of the Study:
- To systematically analyze the origins of the mitochondrial proteome.
- To re-evaluate the endosymbiotic hypothesis using genome evolution models.
- To investigate the evolutionary relationship between eukaryotes and prokaryotes.
Main Methods:
- Analysis of mitochondrial protein domains and their bacterial/archaeal homologues.
- Application of empirical genome evolution models.
- Phylogenetic reconstruction based on genome-scale data.
Main Results:
- 97% of modern mitochondrial protein domains were present in the universal common ancestor (UCA).
- Eukaryotes and Akaryotes (bacteria and archaea) evolved independently from the UCA.
- No significant inter-lineage exchange of coding sequences was detected.
Conclusions:
- The mitochondrial proteome likely evolved autogenically (internally).
- The endosymbiotic origin of mitochondria is not supported by this proteome analysis.
- Eukaryotes and prokaryotes represent parallel evolutionary lineages from a common ancestor.
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