Describe how natural selection can produce balanced polymorphism of allele frequencies through selection that favors heterozygotes.

Key Concepts

Natural Selection

Natural selection is a fundamental mechanism of evolution, where individuals with advantageous traits are more likely to survive and reproduce. This process leads to the gradual adaptation of populations to their environments. In the context of allele frequencies, natural selection can favor certain genotypes over others, influencing the genetic makeup of future generations.

Balanced Polymorphism

Balanced polymorphism occurs when two or more alleles are maintained in a population at stable frequencies due to selective pressures. This often happens when heterozygotes (individuals with two different alleles) have a fitness advantage over homozygotes (individuals with two identical alleles). As a result, both alleles persist in the population, contributing to genetic diversity.

Heterozygote Advantage

Heterozygote advantage is a phenomenon where individuals with two different alleles for a particular gene exhibit greater fitness than those with two identical alleles. This can lead to increased survival and reproductive success, thereby promoting the maintenance of both alleles in the population. A classic example is the sickle cell trait, where heterozygotes are more resistant to malaria, illustrating how natural selection can favor genetic diversity.