The answer is 9%.
To calculate this we will use some
formulas of the Hardy-Weinberg principle:
p² + 2pq + q² = 1 and p + q = 1
where:
p - the frequency of the A allele.
q - the frequency of the a allele.
p² - the frequency of dominant homozygote (with AA genotype)
2pq - the frequency of heterozygote (with Aa genotype)
q² - the frequency of recessive homozygote (with aa genotype)
We know:
p = 70% = 70/100 = 0.7
q = 30% = 30/100 = 0.3
We need to calculate the frequency of the genotype aa:
q² = ?
Since we know the frequency of allele q, it is easy to calculate the frequency of the genotype aa:
q² = 0.3² = 0.09 = 0.09 · 100% = 9%
