RT Journal Article
SR Electronic
T1 Genetic drift suppresses bacterial conjugation in spatially structured populations
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 002980
DO 10.1101/002980
A1 Peter D. Freese
A1 Kirill S. Korolev
A1 José I. Jiménez
A1 Irene A. Chen
YR 2014
UL http://biorxiv.org/content/early/2014/02/24/002980.abstract
AB Conjugation is the primary mechanism of horizontal gene transfer that spreads antibiotic resistance among bacteria. Although conjugation normally occurs in surface-associated growth (e.g., biofilms), it has been traditionally studied in well-mixed liquid cultures lacking spatial structure, which is known to affect many evolutionary and ecological processes. Here we visualize spatial patterns of gene transfer mediated by F plasmid conjugation in a colony of Escherichia coli growing on solid agar, and we develop a quantitative understanding by spatial extension of traditional mass-action models. We found that spatial structure suppresses conjugation in surface-associated growth because strong genetic drift leads to spatial isolation of donor and recipient cells, restricting conjugation to rare boundaries between donor and recipient strains. These results suggest that ecological strategies, such as enforcement of spatial structure and enhancement of genetic drift, could complement molecular strategies in slowing the spread of antibiotic resistance genes.