Q23-5TYU

Question

A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?

(A) 0.7 

(B) 0.49 

(C) 0.42 

(D) 0.21

Step-by-Step Solution

Verified
Answer
  1. The option ‘0.7’ is false.

  2. The option ‘0.49’ is false.

  3. The option ‘0.42’ is true.

  4. The option ‘0.21’ is false.

1Step 1: Fruit fly

In entomology, the tiny two-winged insects that are mainly attracted to and feed on ripened fruits and vegetables and are found everywhere in the world are called fruit flies.

2Step 2: Explanation of option (A)

The principle of population genetics regarding the genetic variation and allele frequency within the population that will remain constant across generations is called the Hardy-Weinberg equilibrium.


Thus, the value 0.7 is only of p, based on the Hardy-Weinberg equilibrium.

Therefore, the given option is false.

3Step 3: Explanation of option (B)

The different conditions involved in the Hardy-Weinberg equilibrium are no mutation, random mating, no natural selection, and a large population size.


Thus, the result of 2pq is 0.42 instead of 0.49.

Therefore, the given option is false.

4Step 4: Explanation of option (C)

When there is a frequent occurrence of a gene in the population of various generations, this frequency is called allele frequency.


Thus, based on the Hardy-Weinberg equation, the remaining recessive allele frequency is 30%, the p will be equal to 0.7, and q is 0.3. The heterozygous allele is obtained by multiplying 2 with p and q. The result will be 0.42.

Therefore, the given option is true.

5Step 5: Explanation of option (D)

The two distinct kinds of alleles based on their traits are recessive and dominant alleles.


Thus, 0.21 is not the correct result obtained from the Hardy-Weinberg equation.

Therefore, the given option is false.