Fig. 4.

The SFS of genealogies reveals differences between pulled and pushed waves. Approximately 100 trees were recorded from simulations of (A) fully pushed, (B) semipushed, and (C) pulled expansions. Each full genealogy was sampled 10 times using a sample size of 20 individuals chosen from the front (see SI Appendix, section 5 for sampling procedure). The resulting SFS, averaged over samples and simulations, is shown with colored dots. The solid line shows the exact predictions for the SFS in each regime (see SI Appendix, section 5 for details).