Nature published “Evolutionary Contingency and its Biophysical Basis in Glucocorticoid Receptor Evolution,” by Mike Harms and Joe. The paper is the culmination of a huge amount of work by Mike at the bench and at the computer. It directly addresses Gould’s classic tape-of-life question — “What would happen if we could replay history from ancestral starting points” — by experimentally characterizing a huge library of alternative “might-have-been” evolutionary trajectories starting from the reconstructed ancestral glucocorticoid receptor. It’s also the first paper in which we have discussed the Persian cavalry. Read it here.