De novo creation of olfactory receptor genes clearly links food odors via amino acid substitutions to cell type differentiation in mosquitoes, and in nematodes, flies, honeybees, etc. It would be surprising if cause and effect did not extend to vertebrates from invertebrates. Indeed, Elekonich and Robinson (2000) linked our 1996 model of RNA-mediated cell type differentiation to hormone-organized and hormone-activated behavior in insects more than a decade ago. Since then, Vosshall’s lab has established the role that amino acid substitutions…