Figure 2.

The influence of sample size in detecting recent population expansions. (a) Demographic model used in the simulations. Times of demographic events (in units of thousands of years, kyr) and population sizes are indicated. (b) The site frequency spectrum for sample sizes of 50 and 2,000 chromosomes. (c) Average value of Tajima's D based on 10⁴ simulation replicates as a function of sample size (number of chromosomes). The lines denote values of Tajima's D from the demographic model in (a) (black line) and a constant sized population (green line). This simulation illustrates the power of large sample sizes for inferring recent demographic events. All information in (b, c) is based on simulating 10 kb of sequence.