title: Evolution of the leucine gene cluster in Buchnera aphidicola: insights from chromosomal versions of the cluster.
abstract: In Buchnera aphidicola strains associated with the aphid subfamilies Thelaxinae, Lachninae, Pterocommatinae, and Aphidinae, the four leucine genes (leuA, -B, -C, and -D) are located on a plasmid. However, these genes are located on the main chromosome in B. aphidicola strains associated with the subfamilies Pemphiginae and Chaitophorinae. The sequence of the chromosomal fragment containing the leucine cluster and flanking genes has different positions in the chromosome in B. aphidicola strains associated with three tribes of the subfamily Pemphiginae and one tribe of the subfamily Chaitophorinae. Due to the extreme gene order conservation of the B. aphidicola genomes, the variability in the position of the leucine cluster in the chromosome may be interpreted as resulting from independent insertions from an ancestral plasmid-borne leucine gene. These findings do not support a chromosomal origin for the leucine genes in the ancestral B. aphidicola and do support a back transfer evolutionary scenario from a plasmid to the main chromosome.
authors.affiliation: Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, 46071 Valencia, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Sabater-Muñoz
authors.forename: Roeland C H J
authors.initials: RC
authors.lastname: van Ham
authors.forename: Andrés
authors.initials: A
authors.lastname: Moya
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Silva
authors.forename: Amparo
authors.initials: A
authors.lastname: Latorre
mesh_terms: D001665:Binding Sites; D020635:Buchnera / Q000235:genetics*; D002876:Chromosomes, Bacterial; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000235:genetics; D007930:Leucine / Q000235:genetics*; D005810:Multigene Family; D010802:Phylogeny; D010957:Plasmids; D011995:Recombination, Genetic
chemical_list: D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C097578:IbpA protein, E coli; C097579:IbpB protein, E coli; D007930:Leucine