Fig. 1.

Allele frequency changes in the first five generations. One generation is defined as one complete life cycle. The trajectories of beneficial mutations with s = 0·1 in three models showing that the frequency of beneficial alleles increases faster from generation 1 to generation 2 if there is a selective advantage in the red-blood-cell stages in the human host (i.e. the host selection and host/transmission selection models). The five differently coloured lines represent independent replicates with the same initial frequency.