Over time,natural selection eliminates individuals with detrimental phenotypes from a population.However,there are several examples in the human population in which harmful genetic polymorphisms are maintained.Why?
A)Individuals with two wild type alleles have advantages over individuals carrying the harmful allele.
B)Individuals with two harmful alleles have advantages over individuals carrying one copy of the harmful allele.
C)Homozygous individuals have some other advantage over individuals with two wild type alleles.
D)Heterozygous individuals have some other advantage over individuals with two wild type alleles.

Question

Quizplus · Accepted Answer

In some cases, heterozygous individuals have an advantage over individuals with two wild type alleles. This is known as heterozygote advantage or "balanced polymorphism." For example, the sickle cell anemia allele can confer resistance to malaria in heterozygous individuals, making them more likely to survive and pass on the allele to their offspring. This can maintain the frequency of the harmful allele in the population. Other examples include the cystic fibrosis allele and the beta-thalassemia allele, which also confer some resistance to certain diseases in heterozygous individuals.

Over Time,natural Selection Eliminates Individuals with Detrimental Phenotypes from a Population.However,there