The one responsible for maintain the presence of this allele
in the population’s gene pool is the heterozygote advantage. It is because the
advantage of having this for a sickle cell disease is that if a person has a
strong heterozygote advantage and that he or she has a copy of the allele that
cause the sickle cell disease, the person will likely be resistant to the
disease because of the heterozygote advantage in which the heterozygote
genotype has a higher relative fitness making it resistant to the disease.
