Models of migration into North Africa.

1Segments from the migrant population were required to be greater than 3 cM in length. Given this minimum threshold, 815 migrant Egyptian and 1,275 migrant South Moroccan segments were discarded.2Two migration models were tested: a “pulse” model assumes a single episode of migration occurred at T0 followed by no further migration, a “continuous” model assumes constant migration from T0 to the present day. Log likelihoods given either model were compared and we present the model with the highest log likelihood.3The maximum likelihood estimate of time since migration initially began “T0” from the migrant population into the admixed: population. We assume prior migration between the populations was zero. Time since migration began T0 is indicated in generations.4The 95% confidence interval was estimated by sampling migrant Egyptian segments (n = 1,246) and migrant South Moroccan segments (n = 2,770) 1,000 times with replacement.