Final answer:
In biology, when heterozygotes demonstrate higher fitness than either homozygote, it is known as heterozygote advantage. This condition increases the value of 2pq over time in a population, as heterozygotes contribute more to the gene pool, leading to an increase in genetic polymorphism and diversity.
Step-by-step explanation:
When heterozygotes have higher fitness than either homozygote, this situation is referred to as heterozygote advantage. Heterozygote advantage is a form of natural selection where the heterozygous genotype has a selective advantage over the homozygous genotypes. As a result, individuals with the heterozygous genotype tend to have higher reproductive success and are more likely to pass their genes to the next generation.
In the context of population genetics, the allele frequencies are often represented by the Hardy-Weinberg equation, p^2 + 2pq + q^2 = 1, where p represents the frequency of one allele, and q represents the frequency of the alternative allele. The term 2pq represents the expected frequency of the heterozygote genotype. If a population is undergoing heterozygote advantage, we would expect the value of 2pq to increase over time because heterozygotes have greater fitness and thus contribute more heavily to the gene pool.
This increase in heterozygosity can preserve genetic polymorphism within a population, as natural selection maintains two or more alleles at a particular gene locus. Situations where a heterozygote exhibits superior fitness can have important implications for the evolutionary dynamics of a population and the maintenance of genetic diversity.