A segment of DNA (an R-factor gene) that has a repeat of an insertion sequence element at each end that can migrate from one plasmid to another within the same bacterium, to a bacterial chromosome, or to a bacteriophage; the mechanism of transposition seems to be independent of the host's usual recombination mechanism.
[L. transpono, pp. transpositum, to transfer, + -on]
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Examples: glitazone, GI cocktail, etc.