Research by Leslie Vosshall's laboratory had previously shown that of 62 odorant-receptor proteins expressed by fruit flies, 61 are exclusively expressed in non-overlapping sub-populations of neurons, indicating that these proteins participate in sensing particular types of odors. However, one odorant receptor protein, Or83b, is found in almost all olfactory neurons and serves a general function in detecting odors. When the gene for Or83b is deleted, the flies can't smell.
In the new study, Vosshall, in collaboration with researchers from Sentigen Biosciences, showed that the function of Or83b is preserved in different insects. Although many odorant-receptor proteins appear to be species specific, there is a high degree of evolutionary conservation of the Or83b coding sequence among the fruit fly, the medfly (a citrus pest), the corn earworm moth (which damages corn and tobacco), and Anopheles gambiae, the malaria mosquito. When the medfly, moth, and mosquito versions (or "orthologues") of Or83b were expressed in fruit flies that were missing their own version of the gene, the flies' sense of smell was restored, arguing not only that the gene's sequence has been conserved over 250 million years of evolution but that the gene's function in olfaction has also been conserved. Future designs of pesticides and disease-controlling insect repellents may be able to utilize this commonality to "blind" the insects to the smell of their prey.
Walton D. Jones, Thuy-Ai T. Nguyen, Brian Kloss, Kevin J. Lee, and Leslie B. Vosshall: "Functional conservation of an insect odorant receptor gene across 250 million years of evolution"