Question

When the heterozygotes in a population have a reproductive advantage, one can predict that _________________________.
A. They will produce only heterozygous offspring
B. The individuals that are homozygous recessive will take over
C. Both homozygous dominant and homozygous recessive individuals will continue to appear in future generations.
D. Homozygous dominant and homozygous recessive individuals will be completely eliminated.

Answer 1

Heterozygous is a condition that has different types of functions from every parent, i.e., it has two different alleles of a particular gene. Here we will see what happens when a heterozygous individual is preferred over homozygous parents.

Complete step by step answer: When a heterozygote in a population has a reproductive advantage, it is termed as heterozygote advantage. Heterozygote advantage is the case wherein the heterozygous genotype has higher relative fitness than homozygous dominant or homozygous recessive genotypes. This case of heterozygote advantage is called over-dominance. It is a condition in which the phenotype of a heterozygous individual is outside the phenotypic range of both the homozygous parents. Heterozygotes have higher relative fitness than homozygotes. By favoring the heterozygotes, polymorphism can be maintained. Which is used to explain genetic variability. An example of heterozygote advantage is the gene that is involved in sickle cell anemia. So, we can say that when there is a heterozygote advantage in a population, only heterozygous offsprings will be reproduced. This is because heterozygous individuals have higher relative fitness than homozygous individuals. Thus, heterozygous individuals will be preferred over homozygous individuals. One common example of heterozygote advantage could be when heterozygous individuals show both advantages and disadvantages but homozygous individuals only show disadvantages. These advantages and disadvantages are rather complex as more than one gene is capable to influence a single trait.
Hence, the correct option is A.

Note: Over-dominance is a genetic condition in which the phenotype of the heterozygote lies outside the phenotypic range of the homozygous parents. The best example of over-dominance is seen in the alleles that code for sickle cell anemia.