The ability to taste PTC is due to a single dominate allele "T". You sampled 215 individuals in biology, and
determined that 150 could detect the bitter taste of PTC and 65 could not. Calculate the frequency of the
heterozygous genotype.
a
72%
b
50%
c
34%
d
17%
To calculate the frequency of the heterozygous genotype, we first need to determine the frequency of the "T" allele in the population.
Let's represent the dominant allele "T" as T and the recessive allele "t" as t.
Since the ability to taste PTC is due to a single dominant allele "T", individuals who can taste PTC can either be homozygous dominant (TT) or heterozygous (Tt).
Given:
- Number of individuals who can taste PTC (Tasters) = 150
- Number of individuals who cannot taste PTC (Non-tasters) = 65
- Total number of individuals sampled = 215
Let's calculate the frequency of the "T" allele first:
Number of Tasters who are TT = 0 (Since tasting PTC requires at least one "T" allele)
Number of Tasters who are Tt = 150 (All of the tasters must have at least one "T" allele, and since there are no TT individuals, they must be Tt)
Total number of Tasters = 150
Number of Non-tasters who are tt = 65 (Non-tasters cannot have the "T" allele, so they must be tt)
Total number of Non-tasters = 65
Total number of individuals with at least one "T" allele = 150 (Tasters with Tt)
Total number of individuals sampled = 215
Frequency of T allele = (Number of individuals with at least one "T" allele) / (Total number of individuals sampled)
Frequency of T allele = 150/215
Frequency of T allele ≈ 0.6977 (or 69.77%)
Now, the frequency of the heterozygous genotype (Tt) can be calculated using the Hardy-Weinberg equation:
Frequency of Tt = 2 * frequency of T allele * frequency of t allele
Frequency of t allele = 1 - frequency of T allele
Frequency of t allele = 1 - 0.6977
Frequency of t allele ≈ 0.3023 (or 30.23%)
Frequency of Tt = 2 * 0.6977 * 0.3023
Frequency of Tt ≈ 0.4220 (or 42.20%)
Therefore, the frequency of the heterozygous genotype (Tt) is approximately 42.20%, which is closest to option a) 72%.