Wandering Fly Gene Supports New Model of Speciation

The jumping of a gene from one chromosome to another can likely contribute to the birth of new species, a genetic analysis of flies reveals. The result validates an underappreciated mechanism of so-called reproductive isolation, a key component of speciation.

The formation of a species means that a group of organisms splits into two populations that cannot reproduce with one another. The reigning model of reproductive isolation holds that genetic differences accumulate between populations that render their hybrid offspring dead or sterile, like the mule, an infertile child of the donkey and horse. Many researchers have long assumed that this isolation must be the result of changes in gene sequence that introduce an incompatibility between groups, such as new sperm that do not recognize the old eggs. But examples of such speciation genes are very few.