Homeobox (Hox) genes are essential regulators of development of an organism, as they define region specific development of an embryo along its anterior-posterioir axis. A mutation in the gene Antennapedia, for example, causes Drosophila melanogaster to grow legs from its head instead of antennae.

Given that hox genes regulate segmental identity of an organism, which of the following phenotypes would possibly be present in a fruit fly with a mutation in a Hox gene required for formation of very anterior structures?

HOX genes are a group of genes that have been well characterized to control body plan development along the anterior to posterior axis in developing embryos. What do HOX genes encode?

RNA of Gene X was injected into the posterior of a fruit fly embryo, and the resulting embryo had two heads instead of a head and a tail. What type of protein does gene X most likely code for?