The sickle-cell allele, which is recessive, causes anemia but confers resistance to malaria in individuals who possess it. however, homozygous recessive individuals often die from anemia but not from malaria, and homozygous dominant individuals do not have anemia but could die from malaria. heterozygous individuals have the highest relative fitness.
this is an example of
a. the heterozygote advantage
b. the homozygous dominant advantage
c. the homozygous recessive advantage
d. genetic drift
e. gene flow

A. the heterozygote advantage

Explanation:

Heterozygote advantage is the condition where the heterozygous individual has higher relative fitness than both homozygous dominant and homozygous recessive individual. This means that the heterozygote individual has higher chances of surviving than both the homozygous counterparts. Sickle cell anemia is a recessive inherited disorder in which oxygen carrying hemoglobin has an abnormal structure. Hence, the resultant RBCs are not spherical but have crescent sickle shape. The oxygen carrying capacity of such RBCs is drastically reduced but they are unaffected by malarial parasite due to their abnormal structure.

in situ hybridization has been widely used for research applications, including clinical cytogenetics, gene mapping, tumor biology and studies of chromosome evolution.