title: The processive kinetics of gene conversion in bacteria.
abstract: Gene conversion, non-reciprocal transfer from one homologous sequence to another, is a major force in evolutionary dynamics, promoting co-evolution in gene families and maintaining similarities between repeated genes. However, the properties of the transfer - where it initiates, how far it proceeds and how the resulting conversion tracts are affected by mismatch repair - are not well understood. Here, we use the duplicate tuf genes in Salmonella as a quantitatively tractable model system for gene conversion. We selected for conversion in multiple different positions of tuf, and examined the resulting distributions of conversion tracts in mismatch repair-deficient and mismatch repair-proficient strains. A simple stochastic model accounting for the essential steps of conversion showed excellent agreement with the data for all selection points using the same value of the conversion processivity, which is the only kinetic parameter of the model. The analysis suggests that gene conversion effectively initiates uniformly at any position within a tuf gene, and proceeds with an effectively uniform conversion processivity in either direction limited by the bounds of the gene.
authors.affiliation: Department of Systems Biology, Harvard University, Boston, MA, 02115, USA.
authors.forename: Johan
authors.initials: J
authors.lastname: Paulsson
authors.affiliation: Department of Systems Biology, Harvard University, Boston, MA, 02115, USA.|School of Biological Sciences, Institute of Cell Biology, The University of Edinburgh, Edinburgh, EH9 3JR, UK.
authors.forename: Meriem
authors.initials: M
authors.lastname: El Karoui
authors.affiliation: Department of Medical Biochemistry and Microbiology, Box 582, Biomedical Center, Uppsala University, Uppsala, S-751 23, Sweden.
authors.forename: Monica
authors.initials: M
authors.lastname: Lindell
authors.affiliation: Department of Medical Biochemistry and Microbiology, Box 582, Biomedical Center, Uppsala University, Uppsala, S-751 23, Sweden.
authors.forename: Diarmaid
authors.identifier: http://orcid.org/0000-0002-7456-9182
authors.initials: D
authors.lastname: Hughes
mesh_terms: D001419:Bacteria / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D005075:Biological Evolution; D053843:DNA Mismatch Repair; D004260:DNA Repair; D005785:Gene Conversion; D007700:Kinetics; D008957:Models, Genetic; D009154:Mutation; D010444:Peptide Elongation Factor Tu / Q000235:genetics; D012475:Salmonella / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D010444:Peptide Elongation Factor Tu