Answer:
The frequency of the s allele is 0.6, the frequency of the S allele is 0.4
SS frequency = 0.16 (16%)
Ss frequency = 0.48 (48%)
ss frequency = 0.36 (36%)
Step-by-step explanation:
When there are two alleles of a gene in a population, the frequency of each allele = 1. That means that the sum of the frequencies of both alleles is 100%
p + q = 1
For our alleles, that means S + s = 1
For the 3 possible genotypes from 3 alleles,
p² + 2pq + q² = 1
For our genotypes, that means S² + 2 x S x s + s² = 1
Since we know that 36 people have the genotype ss, we can add that into our equation:
S² + 2 x S x s + 36 = 1
Therefore, to work out the value of s, we take the square root of 36 (
) = 6.
Therefore s = 6, which we convert to 0.6 (because we are talking about frequencies not percentages)
Back to our initial equation
p + q = 1, so S + s = 1
We know s = 0.6, so
S + 0.6 = 1,
so S = 0.4
For the genotype frequencies
p² + 2pq + q² = 1
0.4² + 2 x 0.4 x 0.6 + 0.6² =1
0.16 + 0.48 + 0.36 = 1
p² is the SS frequency = 0.16
2pq is Ss frequency = 0.48
q² is ss frequency = 0.36