Empirical fitness landscapes reveal accessible evolutionary paths

Missing links recreated Despite the plethora of modern genetic tools, something that is little changed since Darwin's time is our reliance on evolutionary outcomes to unravel the process of evolution. The lack of evolutionary intermediates leaves the door ajar for the proponents of intelligent design. But a new technique could help fill the gaps. It involves the construction of evolutionary intermediates in the lab, and the search for viable paths between them. The resulting 'fitness landscapes' map viable routes between accessible evolutionary paths. When attempting to understand evolution, we traditionally rely on analysing evolutionary outcomes, despite the fact that unseen intermediates determine its course. A handful of recent studies has begun to explore these intermediate evolutionary forms, which can be reconstructed in the laboratory. With this first view on empirical evolutionary landscapes, we can now finally start asking why particular evolutionary paths are taken.