And finally, our gene of the month is Eyeless - a fruit fly gene that has close relatives across the whole animal kingdom. Flies with a faulty version of Eyeless, as you might have guessed, fail to develop eyes. This is because the gene is a kind of master switch that sets up the whole eye-forming process in the developing embryo. The human version of Eyeless is called Pax6, and children who inherit a faulty version are born blind. There are also version of Eyeless in fish, highlighting its importance throughout evolution. By studying Pax6 and Eyeless, researchers are starting to understand how the instructions to make eyes are laid down, as well as gaining important insights into hereditary blindness.