title: Bacterial intra-species gene loss occurs in a largely clocklike manner mostly within a pool of less conserved and constrained genes.
abstract: Gene loss is a major contributor to the evolution of bacterial gene content. Gene loss may occur as a result of shifts in environment leading to changes in the intensity and/or directionality of selection applied for the maintenance of specific genes. Gene loss may also occur in a more neutral manner, when gene functions are lost that were not subject to strong selection to be maintained, irrespective of changes to environment. Here, we used a pangenome-based approach to investigate patterns of gene loss across 15 bacterial species. We demonstrate that gene loss tends to occur mostly within a pool of genes that are less constrained within species, even in those strains from which they are not lost, and less conserved across bacterial species. Our results indicate that shifts in selection, resulting from shifts in environment are not required to explain the majority of gene loss events occurring within a diverse collection of bacterial species. Caution should therefore be taken when attributing differences in gene content to differences in environment.
authors.affiliation: Rachel &Menachem Mendelovitch Evolutionary Processes of Mutation &Natural Selection Research Laboratory, Department of Genetics and Developmental Biology, the Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel.
authors.forename: Evgeni
authors.initials: E
authors.lastname: Bolotin
authors.affiliation: Rachel &Menachem Mendelovitch Evolutionary Processes of Mutation &Natural Selection Research Laboratory, Department of Genetics and Developmental Biology, the Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096, Israel.
authors.forename: Ruth
authors.initials: R
authors.lastname: Hershberg
mesh_terms: D001419:Bacteria / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D019143:Evolution, Molecular; D005798:Genes, Bacterial / Q000235:genetics*; D016680:Genome, Bacterial / Q000235:genetics*; D010802:Phylogeny
chemical_list: D001426:Bacterial Proteins