ASCEND simulation results.
(A) Model of founder event. Consider a population which has experienced a founder event in its past. This history can be divided into three main periods (from the most ancient to the most recent): a period Po where the population has a constant effective population size of No, followed by a period Pb where the effective population size reduces to Nf for the duration of Df generations till Tf generations before present. Then, the population recovers and the population size returns to No during the period PP. We simulated two populations, population A (target) which experienced a founder event and population O (outgroup, no founder event, with constant size No) that diverged 1,800 generations ago. We ran ASCEND and compared the estimated parameters with the true parameters of the founder event in population A. (B) Accuracy in estimating founder age. The X-axis shows the true founder age that was simulated in generations before present (gBP) and the Y-axis shows the founder age estimated by ASCEND. The diagonal represents the expectation (i.e., the case where the estimated values are the same as the true values). We note that for Df > 0 we show a thick band for the diagonal, proportional to duration of the founder event. (C) Accuracy in estimating founder intensity. We define the founder intensity as the ratio of the bottleneck duration over twice the effective population size during the bottleneck, i.e. If = Df/(2Nf). The X-axis shows the true founder intensity, and the Y-axis shows the estimated founder intensity. The diagonal represents the expectation (i.e., the case where the estimated values are the same as the true values).