What are the Evolutionary Origins of Mitochondria? A Complex Network Approach.
Mitochondria originated endosymbiotically from an Alphaproteobacteria-like ancestor. However, it is still uncertain which extant group of Alphaproteobacteria is phylogenetically closer to the mitochondrial ancestor. The proposed groups comprise the order Rickettsiales, the family Rhodospirillaceae, and the genus Rickettsia. In this study, we apply a new complex network approach to investigate the evolutionary origins of mitochondria, analyzing protein sequences modules in a critical network obtained through a critical similarity threshold between the studied sequences. The dataset included three ATP synthase subunits (4, 6, and 9) and its alphaproteobacterial homologs (b, a, and c). In all the subunits, the results gave no support to the hypothesis that Rickettsiales are closely related to the mitochondrial ancestor. Our findings support the hypothesis that mitochondria share a common ancestor with a clade containing all Alphaproteobacteria orders, except Rickettsiales.
General Biology Department, Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil.
Daniel S
DS
Carvalho
General Physics Department, Institute of Physics, Federal University of Bahia, Salvador, Bahia, Brazil.
Roberto F S
RF
Andrade
General Physics Department, Institute of Physics, Federal University of Bahia, Salvador, Bahia, Brazil.
Suani T R
ST
Pinho
Biological Sciences Department, State University of Feira de Santana, Feira de Santana, Bahia, Brazil.
Aristóteles
A
Góes-Neto
Mathematics Department, Institute of Mathematics, Federal University of Bahia, Salvador, Bahia, Brazil.
Thierry C P
TC
Lobão
General Biology Department, Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil.
Gilberto C
GC
Bomfim
General Biology Department, Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil.
Charbel N
CN
El-Hani
D020561:Alphaproteobacteria / Q000737:chemistry / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D005057:Eukaryotic Cells / Q000166:cytology* / Q000382:microbiology; D019143:Evolution, Molecular; D008928:Mitochondria / Q000737:chemistry / Q000235:genetics*; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics; D012281:Rickettsia / Q000737:chemistry / Q000235:genetics*; D020539:Sequence Analysis, Protein
D001426:Bacterial Proteins; D021122:Protein Subunits; D025261:Mitochondrial Proton-Translocating ATPases