This file shows coalescence simulations from population genetics. They simulate the ancestory of sampled gene copies within one or more populations. What is shown is two populations that diverged about 2N generations ago (these are treated as haploids), and the gene is assumed neutral. Shown in green lines within the population "tree" is a simulated gene tree. At right are a whole series of simulated gene trees. Note that the genes sampled from the East and West populations for the most part come out separate in the gene trees (marked by yellow and gray). At lower left is a chart of Slatkin and Maddison's s for 100 gene trees; low values of s indicate there is little mixup among the populations in the gene tree. If the population tree is changed to one with shorter divergence time, the simulated gene trees show much more mixup between east and west (i.e. failure for lineage sorting to have reached completion), and the s values are higher.