Still, in a striking parallel, a gene on the human X chromosome, Dax1, can also encourage female development when present in duplicate. Dax1 also codes for a nuclear hormone receptor. That similarity between worm and human sex determination may be a coincidence, but Meyer sees other reasons for studying worms in such detail. Worms are tractable model organisms for studying the properties and interactions of genes and proteins in detail. And certain types of genes and proteins and the interactions among them recur in seemingly unrelated processes.
Nature goes along and uses whatever's there for new purposes.