Tiny Gene Timing Tweaks Lead to Big Eye Size Differences in Fruit Flies

A new study reveals that minute changes in the timing of a single gene's expression can dramatically alter fruit fly eye size. Researchers compared two closely related fruit fly species, Drosophila mauritiana and Drosophila simulans, finding that subtle differences in the timing of the orthodenticle (otd) gene's expression led to significant variations in the size of ommatidia, the individual units composing the compound eye. Earlier otd expression in D. mauritiana resulted in larger ommatidia and overall larger eyes. This research offers valuable insight into the mechanisms driving organ size evolution.