Transiently beneficial insertions could maintain mobile DNA sequences in variable environments


Edwards, Richard J and Brookfield, John F.Y. (2003) Transiently beneficial insertions could maintain mobile DNA sequences in variable environments. Molecular Biology and Evolution, 20, (1), 30-37. (doi:10.1093/molbev/msg001). (PMID:12519903).

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Description/Abstract

The maintenance of mobile DNA sequences in clonal organisms has been seen as a paradox. If selfish mobile sequences spread through genomes only by overreplication in transposition, then sexuality is necessary for their spread through populations. The persistence of bacterial transposable elements without obvious dominant selectable markers has previously been explained by horizontal transfer. However, advantageous insertions of mobile DNAs are known in bacteria. Here we model maintenance of an otherwise selfish mobile DNA element in a clonal species in which selection for null mutations occurs during one of two temporally alternating environments. Large areas of parameter space permit maintenance of mobile DNAs where, without selection, they would have gone extinct. Horizontal transfer diminishes, rather than enhances, mean copy number. In finite populations, effective population sizes are greatly reduced by selective sweeps, and mean copy number can be increased as the reduced variance in copy number results in reduced selection.

Item Type: Article
ISSNs: 0737-4038 (print)
1537-1719 (electronic)
Keywords: transient insertion mutations, transposable elements, mobile dna, insertion sequences
Subjects: Q Science > QR Microbiology
Divisions: University Structure - Pre August 2011 > School of Biological Sciences
ePrint ID: 151155
Date Deposited: 13 May 2010 12:53
Last Modified: 27 Mar 2014 19:10
URI: http://eprints.soton.ac.uk/id/eprint/151155

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