Question

When explaining dominant and recessive traits to a younger family member, they respond, "Well chances are I can probably taste PTC, since dominant traits are more common." How might you address this misconception?

Answer 1

Dominant traits for PTC aren't more or less common than recessive traits, because neither trait actually increases the chances of a person to survive and reproduce more. This means that the frequency of both traits in the population is roughly 50%. It also largely depends on your genes. If both your biological parents were homozygous dominant for the trait, then you 100% will be able to taste PTC, because you are also homozygous dominant for the trait. If both your parents were homozygous recessive for the trait, then you 100% won't be able to taste PTC, because you are also homozygous recessive for the trait. If only one of your parents was heterozygous, and the other parent was homozygous dominant for that trait, then you may have the recessive allele, but it won't be expressed because it will always be paired with the dominant allele. If only one of your parents was heterozygous and the other parent was homozygous recessive for the trait, then you will have the recessive allele, and there is a 50% chance that the recessive allele, or dominant allele is expressed. If both your parents were heterozygous, then you have a 75% chance of expressing the dominant allele, and a 25% chance of expressing the recessive allele. It largely depends on what your parents have, because the ability to taste PTC isn't something that has the potential to influence your likelihood to reproduce or live longer.

(Dominant allele - Taste PTC)

(Recessive allele - No taste)

Answer 2

Answer:

Dominance of an allele does not make it more frequent in the population.

Explanation:

Dominance is the ability of an allele to mask the effect of another allele of the same gene in heterozygous genotype. The heterozygous genotype would have the phenotype regulated by dominant allele only.  

However, dominance does not increase the frequency of an allele and its respective trait in the population. Frequency of an allele depends on the number of individuals having those alleles.