Question

You are given the following information about a population;

i. there are two alleles C and c.
ii. C codes for green hair and c codes for white hair.
iii. C is dominant over c.
iv. the frequency of the c allele is 0.3
v. the population is comprised of 100 individuals

assuming the population is in hardy weinberg equilibrium how many individuals have green hair?

a)51%
b)9%
c)81%
d)49%

Answer 1

Answer: d - 49% of individuals have green hair.

Explanation: For two alleles, C and c, to be in Hardy-Weinberg equilibrium, p + q must be equal to 1, where p represents the dominant allele C and q represent the recessive allele c.

Allele frequency of c, i.e q has been given as 0.3. Recall that p + q = 1.

Therefore, allele frequency of C, i.e p = 1 - q = 1 - 0.3 = 0.7

Also recall that for a population to reach Hardy-Weinberg equilibrium, p² + 2pq + q² must be equal to 1, where p² represents homozygous dominant allele (CC) , q² represents homozygous recessive allele (cc) and 2pq represent heterozygous alleles (Cc).

Percentage of individuals with green hair, CC is given as p² x total population. That is,

p² x 100 = 0.7 x 0.7 x 100 = 49%

Percentage of individuals with white hair, cc is given as q² x total population. That is,

q² x 100 = 0.3 x 0.3 x 100 = 9%

Percentage of individuals with heterozygous alleles, Cc is given as 2pq x total population. That is,

2pq x 100 = 2 x 0.7 x 0.3 x 100 = 42%