An answer to a complex problem: cloning the mouse t-complex responder.

The t-complex is maintained in wild mouse populations by its high transmission (up to 99%) from heterozygous males and provides an example of "meiotic drive". Its molecular basis has remained obscure despite long and intensive study. In a major advance, the t-complex responder gene, thought to be the key gene on which several distorters act, has now been cloned.