# Population Genetics Problems | MCQ on Hardy-Weinberg equilibrium

1. In sheep, dominant allele B produces white wool and its recessive allele b produces black wool. In a total of 900 sheep, 891 are white and 9 are black. Estimate the frequency of the B allele

A) 0.1

B) 0.9

C) 0.3

D) 0.7

How to Solve : Calculate Gene frequency

2. About 75% of all white North Americans can taste the chemical phenylthiocarbamide and the remainder cannot. The ability to taste is governed by dominant allele ‘T’ and inability to taste by the allele ‘t’. (The population is in Hardy-Weinberg equilibrium). Then the genotypic frequencies are

A) TT–0.5, Tt – 0.3, tt– 0.2

B) TT–0.25, Tt – 0.5, tt– 0.25

C) TT–0.5, Tt – 0.2, tt– 0.3

D) TT–0.3, Tt – 0.5, tt– 0.3

3. Suppose that in a sample of 900 sheep, 891 are white and 9 are black. White wool is dominant over black wool. Estimate the frequency of recessive allele

A) 0.7

B) 0.3

C) 0.9

D) 0.1

4. The genetic effect seen in an isolated population formed by a few individuals of a

species is known as

A) Bottleneck effect

B) Founder effect

C) Assortative effect

D) Random mating

5. The frequency of an allele in a population can be changed by forces like

A) Dominance, family selection, fitness & diversification

B) Selection, mutation, migration, inbreeding & random genetic drift

C) Forward mutation, gene conversion, neutral evolution & recombination

D) Gene interaction, gene transfer, gene mutation & out breeding

6. In a group of students, about 36% could roll their tongues, a trait determined by a dominant gene (R). The other 64% of the students were nonrollers (r) . The population is in Hardy-Wienberg equilibrium. What is the frequency of the gene R and its recessive allele r?

A) R=0.3 and r=0.1

B) R=0.64 and r=0.36

C) R=0.8 and r=0.2

D) R=0.2 and r=0.8

7. In a population, 75% are with dominant phenotype and the rest are with the recessive phenotype. If the population is in equilibrium with respect to this locus, what is the frequency of the dominant allele?

A) 0.5

B) 0.25

C) 0.75

D) 0.407

8. An evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing

A) Bottle-neck

C) Founder effect

9. The random changes in gene frequency occurring by chance and the effect of which is large in small populations is called

A) Hardy-Weinberg equilibrium

B) Pasteur effect

C) Genetic drift

D) Haldane effect

Practice more: Hardy Weinberg Problems

1. B) 0.9

2. B) TT–0.25, Tt – 0.5, tt– 0.25

3. D) 0.1

4. B) Founder effect

5. B) Selection, mutation, migration, inbreeding & random genetic drift

6. D) R=0.2 and r=0.8

7. A) 0.5

8. A) Bottle-neck

9. C) Genetic drift