One gene, many mutations
For deer mice living in the Nebraska Sandhills, color can be the difference between life and death. When the dark-coated mice first colonized the region, they stood out starkly against the light-colored, sandy soil, making them easy prey for predators. Over the next 8,000 years, however, the mice evolved a system of camouflage, with lighter coats, changes in the stripe on their tails, and changes in body pigment that allowed them to blend into their habitat. Now Harvard researchers are using their example to answer one of the fundamental questions about evolution. Is it a process marked by large leaps — single mutations that result in dramatic changes in an organism — or is it the result of many smaller changes that accumulate over time? As described in a March 15 paper in the journal Science, a team of researchers, including former Harvard postdoctoral fellow Catherine Linnen, now an assistant professor at the...