The ability to taste the bitter compound phenylthiocarbamide (PTC) is an autosomal dominant trait. The inability to taste PTC is a recessive condition. In a sample of 500 people, 360 have the ability to taste PTC and 140 do not. Calculate the frequency of the dominant allele.

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Hey, everyone. Let's take a look at this question together in the Hardy Weinberg equation which is P squared plus two P Q plus Q squared is equal to one. What do the variables P and Q represent when calculating allele frequencies in a population? Is it that P represents the frequency of the homozygous alleles? And Q represents the frequency of the heterozygous alleles. Is it that P represents the frequency of the recessive alleles? And Q represents the frequency of the dominant. Is it P represents the frequency of the dominant alleles? And Q represents the frequency of the recessive alleles or is it that P represents the frequency of the heterozygous alleles? And Q represents the frequency of the homozygous alls. Let's work this problem out together to try to figure out what the variables P and Q represent in the Hardy Weinberg equation. So in the Hardy Weinberg equilibrium equation, we have P squared and we know that P squared represents the frequency of the homozygous dominant genotype. However, we want to know what the variable P represents. And since P squared is that frequency of the homozygous dominant genotype where we have two dominant alleles that means that in P squared, the P variable represents that dominant allele. And since P squared is the frequency of the homozygous dominant genotype, that means that Q squared represents the frequency of the homozygous recessive genotype. And since Q squared is the frequency of the homozygous recessive genotype, that means that the variable Q is the recessive allele. Since Q squared is the frequency of the homozygous recessive genotype where we have two recessive alleles, the variable Q represents that recessive allele. And since P is the dominant allele and Q is the recessive allele, that means that answer choice C P represents the frequency of the dominant alleles. And Q represent the frequency of the recessive alleles is the correct answer. Since the Hardy Weinberg equation, which is that P squared plus two P Q plus Q squared is equal to one involves the variables P and Q which P is the frequency of the dominant allele and Q is the frequency of the recessive allele. I hope you found this video to be helpful. Thank you and goodbye.

The ability to taste the bitter compound phenylthiocarbamide (PTC) is an autosomal dominant trait. The inability to taste PTC is a recessive condition. In a sample of 500 people, 360 have the ability to taste PTC and 140 do not. Calculate the frequency of the dominant allele.

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Key Concepts

Autosomal Dominance and Recessiveness

Hardy-Weinberg Principle

Allele Frequency Calculation