title: Direct evidence of recombination in the recA gene of Aeromonas bestiarum.
abstract: Two hundred and twenty-one strains representative of all Aeromonas species were characterized using the recA gene sequence, assessing its potential as a molecular marker for the genus Aeromonas. The inter-species distance values obtained demonstrated that recA has a high discriminatory power. Phylogenetic analysis, based on full-length gene nucleotide sequences, revealed a robust topology with clearly separated clusters for each species. The maximum likelihood tree showed the Aeromonas bestiarum strains in a well-defined cluster, containing a subset of four strains of different geographical origins in a deep internal branch. Data analysis provided strong evidence of recombination at the end of the recA sequences in these four strains. Intergenomic recombination corresponding to partial regions of the two adjacent genes recA and recX (248 bp) was identified between A. bestiarum (major parent) and Aeromonas eucrenophila (minor parent). The low number of recombinant strains detected (1.8%) suggests that horizontal flow between recA sequences is relatively uncommon in this genus. Moreover, only a few nucleotide differences were detected among these fragments, indicating that recombination has occurred recently. Finally, we also determined if the recombinant fragment could have influenced the structure and basic functions of the RecA protein, comparing models reconstructed from the translated amino acid sequences of our A. bestiarum strains with known Escherichia coli RecA structures.
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain. Electronic address: arisanglas@gmail.com.
authors.forename: Ariadna
authors.initials: A
authors.lastname: Sanglas
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain. Electronic address: valbarral@ub.edu.
authors.forename: Vicenta
authors.initials: V
authors.lastname: Albarral
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain; Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain. Electronic address: mfarfan@ub.edu.
authors.forename: Maribel
authors.initials: M
authors.lastname: Farfán
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain. Electronic address: jgloren@ub.edu.
authors.forename: J Gaspar
authors.initials: JG
authors.lastname: Lorén
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain; Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain. Electronic address: mcfuste@ub.edu.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Fusté
mesh_terms: D000333:Aeromonas / Q000235:genetics*; D005798:Genes, Bacterial; D008958:Models, Molecular; D010802:Phylogeny; D011487:Protein Conformation; D011938:Rec A Recombinases / Q000737:chemistry / Q000235:genetics*; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D011938:Rec A Recombinases
keywords: Aeromonas; Aeromonas bestiarum; Molecular marker; Protein prediction; Recombination; recA