Fitness Landscapes & Dynamics of Adaptation: what can we infer from patterns of phenotypic and molecular evolution?

The distribution of fitness effect of new mutations is central to many questions in evolutionary biology such as: what type of genetic variation enables sustained evolution, does adaptation to a given environment entails systematically a cost in different environments, what forces maintain phenotypic and molecular variation we observe in extant populations, etc. Fitness landscapes link the (phenotypic) effect of a new mutation and its fitness consequences. I will present recent work geared at inferring distribution of fitness effects and more broadly the properties of fitness landscapes underlying adaptation. I will consider empirical data bearing both on phenotypic evolution in experimental populations and patterns of molecular variation in natural populations.