About 70% of the human population can taste the bitter chemical phenylthiocarbamide (PTC), which is found in foods like broccoli. The allele, T, for tasting PTC is dominant over the allele, t, for not tasting it. Calculate the allele frequencies using the Hardy-Weinberg equation, where p represents the dominant allele frequency, and q represents the recessive allele frequency. Which of the following is closest to your results?

Question

About 70% of the human population can taste the bitter chemical phenylthiocarbamide (PTC), which is found in foods like broccoli. The allele, T, for tasting PTC is dominant over the allele, t, for not tasting it. Calculate the allele frequencies using the Hardy-Weinberg equation, where p represents the dominant allele frequency, and q represents the recessive allele frequency. Which of the following is closest to your results?

Answer 1

(p+q)^2 = 1

30% of the population have tt:

q^2 = 0.3

p^2 + 2*p*(0.3^0.5) + 0.3 = 1

Solve for p

p^2 is predicted frequency of TT
2*p*q is predicted frequency of Tt
q^2 is predicted frequency of tt

Answer 2

To calculate the allele frequencies using the Hardy-Weinberg equation, we need to know the phenotypic frequencies first. Given that about 70% of the human population can taste PTC, we can assume that the frequency of the dominant allele (T) is 0.70, and the frequency of the recessive allele (t) is 0.30.

Using the Hardy-Weinberg equation:
p^2 + 2pq + q^2 = 1

Where p^2 represents the frequency of the homozygous dominant genotype (TT), 2pq represents the frequency of the heterozygous genotype (Tt), and q^2 represents the frequency of the homozygous recessive genotype (tt).

Let's calculate the allele frequencies step by step:

1. Calculate the frequency of the homozygous dominant genotype (TT):
p^2 = 0.70 * 0.70 = 0.49

2. Calculate the frequency of the homozygous recessive genotype (tt):
q^2 = 0.30 * 0.30 = 0.09

3. Calculate the frequency of the heterozygous genotype (Tt):
2pq = 2 * 0.70 * 0.30 = 0.42

Now, let's check if the equation still holds true:
0.49 + 0.42 + 0.09 = 1

The sum of the frequencies equals 1, which confirms that the equation holds true.

Therefore, the closest result to the calculated allele frequencies would be:
p = 0.70 (frequency of the dominant allele, T)
q = 0.30 (frequency of the recessive allele, t)

Answer 3

To calculate the allele frequencies using the Hardy-Weinberg equation, we need to use the information provided about the phenotypic frequency in the human population.

Given that 70% of the human population can taste PTC, we can derive the frequency of the recessive allele (q) using the formula: q = sqrt(phenotypic frequency).

Let's calculate the frequency of the recessive allele:

q = sqrt(0.70)
q ≈ 0.8367

Since there are only two alleles in this case (T and t), we can calculate the frequency of the dominant allele (p) by subtracting the recessive allele frequency from 1:

p = 1 - q
p ≈ 1 - 0.8367
p ≈ 0.1633

Therefore, the allele frequencies are approximately p = 0.1633 for the dominant allele and q = 0.8367 for the recessive allele.

Now let's consider the answer options and choose the closest one based on our calculations.