If a population is at Hardy-Weinberg equilibrium ...

(i) can you calculate the genotype frequencies if you know the allele frequencies?

(ii) can you calculate the allele frequencies if you know the genotype frequencies?

A. (i) yes; (ii) NO

B. (i) yes; (ii) - yes

C. (i) NO; (ii) yes

B. (i) yes; (ii) - yes

Explanation:

If a population is at Hardy-Weinberg equilibrium, allele frequencies can be calculated from the given values of genotype frequencies and genotype frequencies can be calculated if the allele frequencies are given.

For a population in Hardy-Weinberg equilibrium; p+q=1

Here, p = frequency of recessive allele and q = frequency of dominant allele.

And p2 + 2pq + q2 = 1

p2 = Frequency of homozygous dominant genotype

2pq = Frequency of heterozygous dominant genotype

q2 = Frequency of homozygous recessive genotype

For example, if frequency of homozygous recessive genotype (q2) is 0.40, then, the frequency of recessive allele (q) will be = square root of 0.40 = 0.63

Likewise, frequency of dominant allele (p) in this population will be = 1-q = 1-0.63 = 0.37