This week's picks
Negative Epistasis Between Beneficial Mutations in an Evolving Bacterial Population
In a long-running evolution experiment, fitness increases from combinations of beneficial mutations were less than the sum of their individual benefits.
No small feat: microRNA responses during vocal communication in songbirds
Species without brains often have complex behavioral adaptations, presumably programmed in their DNA. In species with brains, some of the complex decision-making responsibility has moved there. So improvements in behavioral responses can come from learning by individuals, not just evolutionary replacement of poorly adapted genetic strategies with better ones. This paper suggests that RNA can still play a major role in behavior, however, even in species with brains. What I want to know is whether migrating butterflies have navigation instructions programmed into their DNA, leading to consistent changes in gene expression over their migration routes.