Talented newcomer

Natural History, April, 2005 by Stephan Reebs

You might assume that the genes essential to the survival of an organism's genome would have evolved early in the history of the species. But it ain't necessarily so.

Here's how an alternate scenario might work. Imagine taking a job at a well-established corporation. At first your role is minor, but soon you come up with some highly beneficial innovations Your work makes the corporation so successful that your co-workers must adjust to your innovations. Although you're a relative newcomer, you have become powerful--indispensable, in fact.

So it goes for certain genes, according to Benjamin Loppin, a geneticist at Claude Bernard University in Lyon, France, and an international team of molecular biologists. The gene K81, for instance, is vital in some fruit fly species. Without it, sperm cannot fertilize eggs. Yet it appeared "only" between 1 million and 2 million years ago as a misplaced copy of another gene. The original gene still functions throughout the fly's body, but the now-modified copy functions only in the testes (though its exact job has not yet been determined).

How did the flies get by before the duplicate gene appeared? Other genes were probably doing the same job, just not as well, and they were made redundant by the newcomer's innovation. (Current Biology 15:87-93, 2005)