Fig 1. Landscape change options.
The landscape change regimes currently supported by SELVa. In all scenarios, the simulation begins at the root node G with the landscape L0. A, B, C, D are leaf nodes (“extant sequences”), and E and F are internal nodes. “Lightning strikes” denote landscape change events; colors and Li labels correspond to landscapes that govern evolution along the corresponding subtree. (a) The landscape change occurs stochastically: on the branches leading to nodes E, F, A, and D. (b and b’) The landscape change occurs at evenly spaced time intervals (denoted by dashed vertical lines), and the new fitness landscapes are independent for different branches (b) or shared among parallel branches (b’), as reflected in the landscape labels and subtree colors. (c) The landscape change occurs at user-specified branch coordinates t1, t2, t3; with this option, the user may specify the exact fitness vectors describing L1, L2, and L3, or generate these landscapes probabilistically as with the other settings.