title: Molecular considerations in the evolution of bacterial genes.
abstract: Synonymous and nonsynonymous substitution rates at the loci encoding glyceraldehyde-3-phosphate dehydrogenase (gap) and outer membrane protein 3A (ompA) were examined in 12 species of enteric bacteria. By examining homologous sequences in species of varying degrees of relatedness and of known phylogenetic relationships, we analyzed the patterns of synonymous and nonsynonymous substitutions within and among these genes. Although both loci accumulate synonymous substitutions at reduced rates due to codon usage bias, portions of the gap and ompA reading frames show significant deviation in synonymous substitution rates not attributable to local codon bias. A paucity of synonymous substitutions in portions of the ompA gene may reflect selection for a novel mRNA secondary structure. In addition, these studies allow comparisons of homologous protein-coding sequences (gap) in plants, animals, and bacteria, revealing differences in evolutionary constraints on this glycolytic enzyme in these lineages.
authors.affiliation: Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: J G
authors.initials: JG
authors.lastname: Lawrence
authors.forename: D L
authors.initials: DL
authors.lastname: Hartl
authors.forename: H
authors.initials: H
authors.lastname: Ochman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D005075:Biological Evolution; D004755:Enterobacteriaceae / Q000235:genetics; D005798:Genes, Bacterial; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D008322:Mammals / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D010944:Plants / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases