What’s the News: A group of physicists say they've found a way to account for the mysterious radio signals that may be emanating from colonies of E. coli—and it’s not because they’re trying to get our attention. How the Heck:
While human chromosomes are long strings of DNA, bacterial chromosomes are loops. Free electrons travel from atom to atom around such a loop, and as they jump down from one discrete energy level to a lower one, they can emit photons, says a group of researchers, in a recent paper on the arXiv.
The researchers calculate that the transition frequencies of these jumps would be 0.5, 1, and 1.5 kilohertz, about what was reported in an earlier study. In other words, the radio signals could be a result of the quantum nature of electrons and the structure of bacterial DNA.
What’s the Context:
It's suspected that bacteria use waves of higher frequencies to communicate with each other and perform other functions, but radio signals aren't usually discussed in this context.
Radio signals being emitted by bacterial DNA were first observed during a bizarre episode two years ago in which Luc Montagnier, who won a Nobel in 2008 for his discovery of HIV, self-published a paper that seemed to support the idea of homeopathy and involved teleporting DNA (see New Scientist coverage ($) here).
Technology Review’s arXiv blog puts it well:
Let's make one thing clear: this is a controversial area of science. The measurements of bacterial radio waves were published in 2009 by Luc Montagnier, who won the Nobel Prize for medicine in 2008 for the discovery of HIV. However, Montagnier is a controversial figure and it's fair to say that his claims are not accepted by most mainstream biologists. However, one of the criticisms of the work was that there is no known mechanism by which bacteria can generate radio waves. That criticism may now no longer hold.
The Future Holds: A lot more science to back this idea up or disprove it. At the moment, what we have is a theoretical explanation of how the structure of bacterial DNA might make it emit radio signals and some observations by Montagnier that have not been examined in detail. Solid experiments to investigate how bacteria might do this would be very welcome. And once radio signaling has been established, there’s the question of what purpose it serves: What are the bacteria saying? Are they talking to themselves, or others? Or are the signals just the kind of biological flotsam that appears from time to time in evolved creatures—no real purpose, but no threat to reproduction, and hence still hanging around? Reference: Widon, A. et al. Electromagnetic Signals from Bacterial DNA. http://arxiv.org/abs/1104.3113 Image credit: Wikimedia Commons