Hot clock key to fruit fly’s global spread
Heat-sensitive genetic molecule may have enabled some species to survive in wider range of climates
Sometimes, survival of the fittest means dependence on weak links.
Widely distributed fruit fly species have a temperature-sensitive step in the manufacture of a key part in their biological clocks. The heat-sensitive stumbling block may be the reason Drosophila melanogaster and Drosophila simulans have been able to spread to temperate zones while their cousins haven’t, a new study in the Dec. 26 Neuron suggests.
Previously, a research team led by molecular biologist Isaac Edery of Rutgers University in Piscataway, N.J., had discovered that, when the temperature rises, Drosophila melanogaster’s production of a major gear in the clock that governs its daily rhythms melts down. The gear, a protein known as PERIOD, helps set the circadian clock in fruit flies and many other animals.
Fruit flies are active in the morning, take a siesta during the hottest part of the day, then wake up and move around again in the early evening when it is cooler. The siesta helps keep the flies from over-heating and drying out. PERIOD protein builds up during the siesta period until it reaches high enough levels to set off the flies’ inner alarm clocks and rouse them for the evening.