Abstract
In vitro protein evolution is comprehended as a hill-climbing process on a fitness landscape in sequence space, just like the protein folding is comprehended as a valley-descending process on an energy landscape in comformation space. In this review, based on a mathematical model for in vitro molecular evolution, we demonstrated an analogy between evolutionary dynamics and thermodynamics and then many concepts in evolutionary dynamics became comprehensible. By introducing thermodynamics-like concepts such as “free fitness”, it is interpreted that evolution is driven in the direction in which free fitness increases. In this process, the evolving population climbs the fitness landscape by absorbing “fitness information” as the negative entropy from the surroundings as an experimental set-up.
