ECONOMIST on BIOLOGY

NATURE is full of surprises. When atoms were first proved to exist (and that was a mere century ago), they were thought to be made only of electrons and protons. That explained a lot, but it did not quite square with other observations. Then, in 1932, James Chadwick discovered the neutron. Suddenly everything made sense—so much sense that it took only another 13 years to build an atomic bomb.
It is probably no exaggeration to say that biology is now undergoing its “neutron moment”. For more than half a century the fundamental story of living things has been a tale of the interplay between genes, in the form of DNA, and proteins, which the genes encode and which do the donkey work of keeping living organisms living. The past couple of years, however, have seen the rise and rise of a third type of molecule, called RNA.
The analogy is not perfect. Unlike the neutron, RNA has been known about for a long time. Until the past couple of years, however, its role had seemed restricted to fetching and carrying for DNA and proteins. Now RNA looks every bit as important as those two masters. It may, indeed, be the main regulator of what goes on in a cell—the cell's operating system, to draw a computing analogy—as well as the author of many other activities (see article). As important, molecular biologists have gone from thinking that they know roughly what is going on in their subject to suddenly realising that they have barely a clue.