Interact box Coalescent genealogies in populations with changing size

The coalescent process can be simulated for populations experiencing exponential growth in population size through time. The simulation displays a genealogy based on values for the number of lineages (n:) and the growth rate of the population (exp:). The growth rate parameter corresponds to the rate of exponential population growth and is therefore the key variable in this simulation. Click the Recalc button to begin a new simulation. The resulting genealogy can be viewed as an animation going back in time (click Animation tab at top left and use playback controls at bottom) or as a genealogy (click Trees tab at top left).

Set the growth rate parameter to 0 and click Recalc. View the resulting genealogy. Then set the growth rate parameter to 128 and click Recalc and view the results. How do the genealogies in growing populations compare with genealogies when population size is constant over time? Re-run the simulation a few times for both values of the growth rate parameter. Also try other less extreme values of the growth rate parameter, such as 4, 8, and 32.

previous section, the exponential distribution of coalescence waiting times was obtained by relying on the fact that the probability of non-coalescence, or k-1

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