Figure 2.

Three examples of gene genealogies for 30 chromosomes sampled randomly from a population that currently includes 50,000. All three genealogies correspond to constant-sized populations that underwent sudden, 100-fold expansions 7,000 generations in the past. Associated allele length distributions are shown below for each figure and are obtained by distributing stepwise mutations along the genealogy with an average frequency of 0.00056 per generation. The numbers at the bottom of each genealogy show the change in allele length from the ancestral chromosome to each of the sampled chromosomes.