title: Evolution of bacterial recombinase A (recA) in eukaryotes explained by addition of genomic data of key microbial lineages.
abstract: Recombinase enzymes promote DNA repair by homologous recombination. The genes that encode them are ancestral to life, occurring in all known dominions: viruses, Eubacteria, Archaea and Eukaryota. Bacterial recombinases are also present in viruses and eukaryotic groups (supergroups), presumably via ancestral events of lateral gene transfer. The eukaryotic recA genes have two distinct origins (mitochondrial and plastidial), whose acquisition by eukaryotes was possible via primary (bacteria-eukaryote) and/or secondary (eukaryote-eukaryote) endosymbiotic gene transfers (EGTs). Here we present a comprehensive phylogenetic analysis of the recA genealogy, with substantially increased taxonomic sampling in the bacteria, viruses, eukaryotes and a special focus on the key eukaryotic supergroup Amoebozoa, earlier represented only by Dictyostelium We demonstrate that several major eukaryotic lineages have lost the bacterial recombinases (including Opisthokonta and Excavata), whereas others have retained them (Amoebozoa, Archaeplastida and the SAR-supergroups). When absent, the bacterial recA homologues may have been lost entirely (secondary loss of canonical mitochondria) or replaced by other eukaryotic recombinases. RecA proteins have a transit peptide for organellar import, where they act. The reconstruction of the RecA phylogeny with its EGT events presented here retells the intertwined evolutionary history of eukaryotes and bacteria, while further illuminating the events of endosymbiosis in eukaryotes by expanding the collection of widespread genes that provide insight to this deep history.
authors.affiliation: Department of Zoology, Universidade de São Paulo/USP, Cidade Universitária, São Paulo, Brazil.
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Hofstatter
authors.affiliation: Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS 39762, USA.
authors.forename: Alexander K
authors.initials: AK
authors.lastname: Tice
authors.affiliation: Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS 39762, USA.
authors.forename: Seungho
authors.initials: S
authors.lastname: Kang
authors.affiliation: Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS 39762, USA matthew.brown@msstate.edu.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Brown
authors.affiliation: Department of Zoology, Universidade de São Paulo/USP, Cidade Universitária, São Paulo, Brazil dlahr@ib.usp.br.
authors.forename: Daniel J G
authors.identifier: 0000-0002-1049-0635
authors.initials: DJ
authors.lastname: Lahr
mesh_terms: D056894:Amoebozoa / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D004023:Dictyostelium / Q000201:enzymology / Q000235:genetics; D056890:Eukaryota / Q000201:enzymology / Q000235:genetics*; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D010802:Phylogeny; D011938:Rec A Recombinases / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D011938:Rec A Recombinases
keywords: Amoebozoa; DNA repair; endosymbiotic gene transfer; mitochondria; recA; recombinase