Why are some olfactory receptors conserved across species?

The sense of smell is crucial to the fitness of most animals.

Insects detect odors using chemoreceptors from two gene families: odorant receptors (ORs) and ionotropic receptors (IRs). The receptor genes evolve fast, and most of them are therefore highly divergent between different species. Yet, some receptors are conserved in related species, and a few may even exist throughout an insect order.

The outstanding question is why some receptors are conserved when most are not, and whether they fulfill the same olfactory roles in different species.

This project aims to reveal whether conserved chemoreceptor orthologs detect the same odors (i.e., are functionally conserved) in different species within and between taxonomic insect families, which would suggest that such odors are relevant to the ecology and fitness of many species.

Functions will be studied broadly using both ORs and IRs, conserved to different extents in the largest animal order – Coleoptera (beetles).

Furthermore, the poorly understood mechanisms of odor binding that determine response specificity will be studied in the receptors that will be functionally characterized.

The prediction is that receptors that respond to the same odors in different species bind the odors using the same conserved amino acid residues.

The project will contribute new insight into the functional and molecular evolution of two of the largest gene families in arthropods, including the first functional characterization of IRs in beetles.