Bio Grad Songhui Zhao, Neurobiology grad Bryson Deanhardt (co-first authors), and Professor Pelin Volkan have published significant findings in Science Advances: “Chromatin-based reprogramming of a courtship regulator by concurrent pheromone perception and hormone signaling.” It has been understood that mature male flies use their sense of smell to determine when and with whom to mate, and further that male flies raised in isolation are less able to detect female pheromones. This paper describes for the first time the molecular mechanism governing these decisions.
When raised in a group, as male fruit flies age they increase the expression of a courtship gene called 'fruitless' which helps them detect other flies’ pheromones. This gene is wrapped tightly in chromatin, which must loosen enough to expose the gene’s “on” switch. In isolated flies the chromatin never loosens, and the fly's behavior remains correspondingly constricted. Fortunately for them, however, putting them in with a group or just exposing them to other flies’ pheromones causes the chromatin to relax and free the gene, along with its inhibited owner.