A population of sexually reproducing organisms with non-overlapping generations has two alleles: A1 and A2; p is the frequency of A1, q is the frequency of A2 (p+q=1). Allele A2 is recessive and lethal when in homozygous genotype (i.e. fitness of A2A2 is zero). Fitness of heterozygote is the same as that of dominant homozygote (full dominance for fitness).

Assume q=0.01. Calculate allele and genotype frequencies for three successive generations of this population (directional or purifying selection). Explain why delta p will change with generations.