Question

Question 5: Answer and give explanation In a sample of 400 men, 48 have X-linked color blindness and all the others have normal color vision. What is the frequency for the X-linked color blindness allele, assuming each man is hemizygous for the allele? A) 0.1 B) 0.12 C) 0.24 D) 0.48 E) 0.88 In a population, whenever the second most frequent allele of a gene has a frequency greater than 0.01, we refer to the situation as a: A) Genetic polymorphism B) Genetic anomaly C) Genetic mutation D) Genetic abnormality E) Genetic variant Which of the following is most effective at fixing the recessive allele in a population? A) Selection for a recessive allele B) Selection against a recessive allele C) Selection against homozygous recessive individuals D) Selection against heterozygotes E) Selection against both heterozygous and recessive individuals Selection that favors intermediate values of a trait at the expense of extreme values is known as: A) Directional B) Disruptive C) Stabilising D) Negative E) Purifying Selection that favors extreme values of a trait at the known as: A) Directional B) Disruptive C) Balancing D) Negative E) Purifying expense of intermediate values is The decay of heterozygosity in a population is proportional to A) 2N B) 1/4N C) 1/2N D) 1-2N E) 1-1/4N

Answer 1

1. Ans: A) 0.1

Explanation: Total population 400

48 are colour blind

So, their frequency is (48/400) = 0.1

As, colour blindness is X-linked and they are hemizygous, so, only one allele is present for that.

So, the allele frequency is same as 0.1.

2) Ans: A (Genetic polymorphism)

Explanation: Geneic polymorphism is a case, when multiple alleles are present at a locus, and in that case at least two alleles occur with a higher frequency.

3) Ans: A (Selection for a recessive allele).

4) Ans: C (Stabilising selection)

Explanation: Stabilising selection is an example of natural selection, where the population mean stabilizes the non-extreme trait (intermediate value) value.

5) Ans: B (disruptive selection)

Explanation: This is a type of selection where extreme values for a trait get favoured over the intermediate values.

6) Ans: C (1/2N)