Evolution of genomic proportions under neutral admixture and immigration. The evolution of genomic proportions under neutral admixture with ongoing gene flow. The simulated population as founded by equal numbers from each parental species at t = 0. Population size was held constant at 100 diploids. Each generation, resident adults were replaced by pure parental genotypes with probability 0.10 (average gene flow was Nm = 10 each generation. Offspring genotypes (before dispersal) for 100 diagnostic 2-allele codominant markers were tracked over 200 non-overlapping generations of immigration, random mating, and genetic drift.