Question

The frequency of the allele for blood type B in a country is represented as 30 out of every 100 people. Type A’s frequency is found in 40 out of every 100 people. Given those two frequencies, what is the frequency of the recessive type O allele? Use either decimal or whole number % to answer this.

Answer 1

In this case, we assume that there are only three alleles for blood type: A, B, and O. Since blood type B has a frequency of 30 out of every 100 people, the frequency of the B allele is 30/100 or 0.30. Similarly, the frequency of the A allele is 40/100 or 0.40.

We can use the fact that the frequencies of all the alleles must add up to 1 to find the frequency of the O allele. That is:

Frequency of A allele + Frequency of B allele + Frequency of O allele = 1

Solving for the O allele frequency:

Frequency of O allele = 1 - Frequency of A allele - Frequency of B allele
Frequency of O allele = 1 - 0.40 - 0.30
Frequency of O allele = 0.30 or 30%

Therefore, the frequency of the recessive type O allele is 0.30 or 30%.