LIGHTNING is nature鈥檚 own genetic engineer. By opening up pores in soil bacteria it allows them to pick up any stray DNA present, report Timothy Vogel, Pascal Simonet and their colleagues at the University of Lyon in France. This hitherto unknown phenomenon might help explain why gene swapping is so common among bacteria.
Mild electric shocks are routinely used to genetically engineer bacteria in the lab, so Vogel and Simonet wondered whether lightning could have the same effect. Although it would kill bacteria near the point of contact, those further away would get a milder shock.
The researchers persuaded physicist colleagues to blast bacteria with artificial lightning. So far they have shown that two strains of the soil bacterium Pseudomonas as well as a lab strain of E. coli take up 鈥渂ait鈥� DNA when zapped by lightning (Applied and Environmental Microbiology, DOI: 10.1128/AEM.70.10.6342-6346.2004).
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The researchers suspect the phenomenon is widespread, speeding up the rate at which bacteria evolve. Genetic studies show bacteria frequently pick up foreign genes, usually from other bacteria, but natural DNA uptake rates are too sluggish to explain the observed diversity. Lightning might also have speeded up the evolution of the first bacteria, Vogel says.