Fig. 1.

(A) An example of a demographic model with a genealogy. A 2-population isolation with migration (IM) model includes six parameters: population sizes, ${\theta }_1,{\theta }_2$ and θ_a, migration rates, m₁ and m₂, and splitting time T_s. The graph in black lines depicts a genealogy (G) including coalescent events at time t₁ and t₂, respectively, (vertical paths of genes) and migration events (horizontal paths). (B) The coalescent tree (λ₁) of genealogy G includes the same coalescent events on G. (C) A coalescent tree λ₂ whose probability is same as that of λ₁. (D) Genealogy and coalescent tree with population labels.