Figure 2.

(A) Scenarios explaining the disjunct distribution of current H. niger populations. In the left and middle pane, pre-glacial vicariance or a pre-glacial founder event led to the split of the ancestral population into the current populations 1 and 2. In the right pane, a post-glacial founder event gave rise to population 2 from the ancestral population 1. See detailed description in the Introduction section. (B) Summary of models simplifying particular scenarios in (A), tested using demographic models in dadi. All models tested are shown and described in Supplementary Figure 1. Numbers 1 and 2 refer to current populations (i.e., genetic groups defined based on STRUCTURE analysis); gene flow is indicated by arrows.