FIGURE 2.

Schematic of competing scenarios 1–3 tested in diyabc (Cornuet et al., 2014) to evaluate the relative probability of (a) divergence followed by secondary contact (Scenario 1), (b) ongoing gene flow or very recent and incomplete divergence (Scenario 2) with the alternative topologies 2a and 2b, (c) and the role of a bottleneck (shown with the transition from a thick to thin line; Scenario 3) in shaping the patterns of genetic variation observed in G. f. fuscipes populations in Uganda. Each panel shows the topology and population fluctuations specified in the scenario, wherein Ne was free to vary 100–30,000, or 100–5,000 during a bottleneck. Time priors are shown in shading (not to scale) and are labeled on the right of each scenario (t4 = 340–360 ka, t3 = 20–40 ka, t2 = 10–20 ka, t1 = 5–135 years ago). “ra” refers to rate of admixture, and was allowed to vary from 0 to 1. “bd” refers to the bottleneck duration, and was allowed to vary from 1.25 to 5,000 years ago (Supporting Information Table S3), which corresponds to a final desiccation event that was thought to occur in the Lake Kyoga region (Danley et al., 2012).