In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20% of the β h
emoglobin alleles in the human gene pool. Although selection is clearly present, if the ideal equilibrium of alleles existed, what should be the proportion of heterozygous individuals in populations that live here?
The proportion of the recessive sickle cell anemia allele in the given population is 20%. So, the frequency of the recessive allele in the population would be 20% or 0.2.
The population is said to be following the ideal equilibrium of alleles. Therefore, the frequency of the corresponding dominant allele for the locus would be= 1- frequency of the recessive allele = 1- 0.2 = 0.8
The frequency of the heterozygous individuals in the population= 2 x proportion of the dominant allele in the population x frequency of the recessive allele = 2 x 0.8 x 0.2 = 0.32 or 32%
