Problem
The human b-globin gene has two alleles, HS and HA. Individuals that are homozygous for HS have sickle-cell anemia and a lower fitness. Individuals that are heterozygotes (HSHA) do not show sickle-cell symptoms and have a resistance to malaria. Individuals that are homozygous for HA have the highest fitness but are susceptible to malaria. If a vaccine for malaria was created that was 100% effective, affordable, and widely available, what would happen to the frequency of the HS allele?