Question

Explain how the principle of dominance is unrelated to an allele’s frequency in a population . Ex. how a dominant allele can be rare

Answer 1

In this case, remember that the principle of dominance applies for the phenotypic frequency of a determined population and the allele frequency applies for the number of each allele in a population regardless of whether it is dominant or not. In a population, we can find a rare dominant allele if that allele produces a non beneficial phenotype for the individuals, producing a phenomenon of natural selection. Another way is that the heterozygous genotype confers an advantage for the individual, increasing only the heterozygous genotype but with high frequency of the recessive allele.