Sickle cell anemia is a recessive trait (aa) which causes a red blood cell disorder in which there aren't enough healthy red blood cells to carry oxygen to the body. Individuals with the genotype AA have normal red blood cells. Those individuals who are heterozygous for the trait usually have no symptoms of sickle cell disease, but carry the sickle cell trait and can pass it on to their offspring. However, those individuals who carry the sickle cell trait have some protective advantage against malaria, making this a common genotype in malaria prone areas. The graph illustrates the frequencies of two genotypes, AA and Aa, over many generations. Select ALL the conclusions you can draw from the graph provided. A) There appears to be random mating between genotypes.
B) There is no selective advantage for one genotype over another.
C) This graph probably represents a population in a malaria-prone area.
D) The population reached equilibrium for these traits at about generation 35.
E) Sickle cell disease has died out of this population and will most likely not return.