Question

There is a population of Drosophila flies in a small fruit shop

Answer 1

The answer is A. p2 = 0.36, 2pq = 0.48, q2 = 0.16.

Let's first distinguish alleles frequencies from genotypes frequencies:
p - a frequency of R allele,
q - a frequency of r allele,
p² - a frequency of RR genotype,
2pq - a frequency of Rr genotype,
q² - a frequency of rr genotype.

The gene frequency of allele r changes from 0.38 to 0.40, thus:
q = 0.40

Now, we will implement this in the following equation:
p + q = 1

If q = 0.40, then:
p + 0.40 = 1
⇒ p = 1 - 0.40
⇒ p = 0.60

Now, the frequencies of both alleles are know and it is easy to calculate the genotype frequencies:
- the frequency of RR genotype: p² = 0.60² = 0.36
- the frequency of Rr genotype: 2pq = 2 · 0.60 · 0.40 = 0.48
- the frequency of rr genotype: q² = 0.40² = 0.16

Therefore, the new genotype frequencies in that population are p2 = 0.36, 2pq = 0.48, q2 = 0.16.