Comparative genomic analysis of the odorant-binding protein family in 12 <Emphasis Type="Italic">Drosophila</Emphasis> genomes: purifying selection and birth-and-death evolution

Background  

Chemoreception is a widespread mechanism that is involved in critical biologic processes, including individual and social behavior. The insect peripheral olfactory system comprises three major multigene families: the olfactory receptor (Or), the gustatory receptor (Gr), and the odorant-binding protein (OBP) families. Members of the latter family establish the first contact with the odorants, and thus constitute the first step in the chemosensory transduction pathway.