Key connection
For more than a century, scientists have suggested that the best way to settle the debate about how phenotypic plasticity — the way an organism changes in response to environment — may be connected to evolution would be to identify a single mechanism that controls both. Harvard researchers say they have discovered just such a mechanism in insulin signaling in fruit flies. Cassandra Extavour, an associate professor of organismic and evolutionary biology, and grad student Delbert André Green II were able to show that a single molecular pathway plays a role in both heritable changes in the flies’ number of ovarioles — egg-producing compartments in the ovaries — and in how they react to their environments by shutting down some ovarioles. The study is described in a paper published this month in the Proceedings of the Royal Society B. “This is the first example, to my knowledge, that shows this link —...