Figure 4. Isolation with migration models as estimated in MSMC-IM. On left, estimates of migration rates through time for each species. On right, the cumulative migration probabilities throughout the past 500,000 years. In species with a single peak on the left and a steep slope on the right, we would infer a single period of differentiation followed by isolation. In contrast, species with multiple or extended peaks on left plots indicate multiple or prolonged bouts of gene flow between differentiating populations. Population differentiation is inferred to be occurring when 0 < M(t) < 1.