Publication Date:
2016-02-04
Description:
The origin of eukaryotes stands as a major conundrum in biology. Current evidence indicates that the last eukaryotic common ancestor already possessed many eukaryotic hallmarks, including a complex subcellular organization. In addition, the lack of evolutionary intermediates challenges the elucidation of the relative order of emergence of eukaryotic traits. Mitochondria are ubiquitous organelles derived from an alphaproteobacterial endosymbiont. Different hypotheses disagree on whether mitochondria were acquired early or late during eukaryogenesis. Similarly, the nature and complexity of the receiving host are debated, with models ranging from a simple prokaryotic host to an already complex proto-eukaryote. Most competing scenarios can be roughly grouped into either mito-early, which consider the driving force of eukaryogenesis to be mitochondrial endosymbiosis into a simple host, or mito-late, which postulate that a significant complexity predated mitochondrial endosymbiosis. Here we provide evidence for late mitochondrial endosymbiosis. We use phylogenomics to directly test whether proto-mitochondrial proteins were acquired earlier or later than other proteins of the last eukaryotic common ancestor. We find that last eukaryotic common ancestor protein families of alphaproteobacterial ancestry and of mitochondrial localization show the shortest phylogenetic distances to their closest prokaryotic relatives, compared with proteins of different prokaryotic origin or cellular localization. Altogether, our results shed new light on a long-standing question and provide compelling support for the late acquisition of mitochondria into a host that already had a proteome of chimaeric phylogenetic origin. We argue that mitochondrial endosymbiosis was one of the ultimate steps in eukaryogenesis and that it provided the definitive selective advantage to mitochondria-bearing eukaryotes over less complex forms.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780264/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780264/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pittis, Alexandros A -- Gabaldon, Toni -- England -- Nature. 2016 Mar 3;531(7592):101-4. doi: 10.1038/nature16941. Epub 2016 Feb 3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG), Carrer del Dr Aiguader, 88, 08003 Barcelona, Spain. ; Departament of Ciencies Experimentals I de La Salut, Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain. ; Institucio Catalana de Recerca i Estudis Avancats (ICREA), Passeig de Lluis Companys 23, 08010 Barcelona, Spain.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26840490" target="_blank"〉PubMed〈/a〉
Keywords:
Eukaryotic Cells/*cytology/metabolism
;
Genes, Bacterial/*genetics
;
Genes, Mitochondrial/*genetics
;
Genomics
;
Mitochondria/*genetics/metabolism
;
Mitochondrial Proteins/genetics/metabolism
;
Models, Biological
;
*Phylogeny
;
Prokaryotic Cells/*cytology/metabolism
;
Symbiosis/*genetics
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
