Sickle-cell anemia is a genetically inherited disease. Homozygous individuals (SS) have normal blood cells that are easily infected with the malarial parasite. Thus, many of these individuals become ill and may die. Individuals homozygous for the sickle-cell trait (ss) have sickled red blood cells that readily collapse when deoxygenated. Although malaria cannot grow in these red blood cells, individuals often die because of the hemoglobin disorder. However, individuals with the heterozygous condition (Ss) have some sickling of red blood cells, but generally not enough to cause death. In addition, the heterozygotes tend to survive better than either of the homozygous conditions as they are resistant to malaria. If 16% of an African population is born with a severe form of sickle-cell anemia (ss), what percentage of the population will be heterozygous (Ss) for sickle-cell and therefore resistant to malaria?
