Table 2.

A comparison of the simulation models of Liu et al. (2006) and our present model. (Only major differences are mentioned.)

	Liu et al. (2006)	our present model
number of demes in total	300	251
population growth	logistic growth; initial growth rate variable, and finally estimated to be 1.86	logistic growth with a growth rate fixed at 1.8
carrying capacity	variable parameter; carrying capacity of Africa estimated at 1064; all other demes at 750	variable parameter; all demes have the same carrying capacity
colonization and exchange rate	aggregated under a single value for migration rate, which is variable, and estimated to be 0.115 in each of the two directions	separate; both vary independently
origin of expansion	at the left edge of the array of demes	in the interior of the deme array, with 50 demes on the left and 200 on the right
predicted pattern of variation of heterozygosity with geographical distance from the origin of expansion	nonlinear decay	linear decay with a boundary effect for the populations at the edges of the grid