Feminizer and doublesex knock-outs cause honey bees to switch sexes.

Honey bees are experts at refuting societal norms. Their matriarchal hives are headed by queens, backed by an all-female workforce, and males die soon after copulation. But the biochemical basis of how these distinct castes and sexes (queens, workers, and drones) arise is poorly understood, partly due to a lack of efficient tools for genetic manipulation. Now, Roth and colleagues have used clustered regularly interspaced short palindromic repeats (CRISPR) to knock out two key genes (feminizer and doublesex) that guide sexual development. Their technique yielded remarkably low rates of genetic mosaicism and offers a promising tool for engineering and phenotyping bees for diverse applications.