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DO PHAGES EFFICIENTLY SHUTTLE TRANSPOSABLE ELEMENTS AMONG PROKARYOTES?
Author(s) -
Leclercq Sébastien,
Cordaux Richard
Publication year - 2011
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2011.01395.x
Subject(s) - transposable element , biology , plasmid , mobile genetic elements , horizontal gene transfer , genome , genetics , dna transposable elements , insertion sequence , selection (genetic algorithm) , genome evolution , positive selection , evolutionary biology , gene , artificial intelligence , computer science
The distribution, dynamics, and evolution of insertion sequences (IS), the most frequent class of prokaryotic transposable elements, are conditioned by their ability to horizontally transfer between cells. IS horizontal transfer (HT) requires shuttling by other mobile genetic elements. It is widely assumed in the literature that these vectors are phages and plasmids. By examining the relative abundance of IS in 454 plasmid and 446 phage genomes, we found that IS are very frequent in plasmids but, surprisingly, very rare in phages. Our results indicate that IS rarity in phages reflects very strong and efficient postinsertional purifying selection, mainly caused by a higher density of deleterious insertion sites in phages compared to plasmids. As they do not tolerate IS insertions, we conclude that phages may be rather poor vectors of IS HT in prokaryotes, in sharp contrast with the conventional view.