Question

Assume that the ability or inability to fold the tongue is controlled by a single locus with two alleles: the ability to fold the tongue is dominant and controlled by A allele, while the inability to fold the tongue is a recessive trait controlled by the recessive allele, a.

A class of 100 students was asked if they could fold their tongues. Out of all the students in the class, 25 couldn’t fold their tongues while the remaining 75 could. What is the frequency of the aa genotype in the class?

Select one:

0.10

0.20

0.25

0.50

0.75

Question 2:

Assuming the class is in Hardy-Weinberg equilibrium, what is the frequency of the a allele in the class?

Select one:

0.10

0.20

0.25

0.50

0.75

Question 3:

Assume that the ability or inability to fold the tongue is controlled by a single locus with two alleles: the ability to fold the tongue is dominant and controlled by A allele, while the inability to fold the tongue is a recessive trait controlled by the recessive allele, a.

A class of 100 students was asked if they could fold their tongues. Out of all the students in the class, 25 couldn’t fold their tongues while the remaining 75 could. What is the frequency of the aa genotype in the class?

Select one:

0.10

0.20

0.25

0.50

0.75

Answer 1

2. The correct answer is 0.25. Here A is dominant over a. The stuents with ability to rotate tongue will have genotype either AA or Aa while the students without ability to rotate the tongue will have genotype aa. Here out of 100 only 25 could not rotate the tongue it means those 25 studentds will have aa geneotype and thus the frequency of genotype aa will be 25/ 100 = 0.25.

3. The correct answer is 0.5. In the condition of Hardy-Weinberg equilibrium: p² + 2pq + q² = 1 and p + q = 1 (Where p represents A and q represents a, p² represents the frequency of AA, q² represents frequency of aa and 2pq represents frequency of Aa)

Here q² = 0.25 (determined in question 2)

Therefore q = 0.5

Since p + q = 1 therefore p + 0.5 = 1 and thus p = 1 - 0.5 = 0.5

Hence the frequency for allele a will be 0.5