Have Your DNA and Eat It Too

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Science  26 Oct 2001:
Vol. 294, Issue 5543, pp. 747-749
DOI: 10.1126/science.294.5543.747e

Bacteria readily consume extracellular DNA by various mechanisms. The acquisition of foreign DNA contributes to horizontal gene transfer and is of experimental utility. Finkel and Kolter now offer data to show that homo- and heterospecific DNA can fully support the growth of Escherichia coli in the absence of other nutrients. Not all bacteria, including E. coli, are naturally competent for genetic transformation; after all, recombination with heterologous DNA is risky. Tellingly, for several species, competence (mediated by the com family of genes) is induced only by starvation. Despite lacking natural competence, E. coli possesses com gene homologs that, if mutated, destroy its capacity to compete with wild-type bacteria during stationary phase, presumably because the mutants no longer can eat the DNA released into the medium from dying bacteria.—CA

J. Bacteriol.183, 6288 (2001).

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