Question

In a given population, only the "a" and "b" alleles are present in the abo system; there are no individuals with type "o" blood or with o alleles in this particular population. if 200 people have type a blood, 75 have type ab blood, and 25 have type b blood, what are the alleleic frequencies of this population (i.e., what are p and q)

Answer 1

The frequency of allele is illustrated as the ratio of that specific allele in the population. As one knows that as the humans are diploid, so the total number of alleles is double of the total number of people in the population.

In order to determne the allele frequencies for A and B, there is a need to know that the persons with type A blood are homozygous AA, the persons with type AB blood are heterozygous AB, and the persons with type B blood are homozygous BB.

The frequency of A is:

2*(number of AA) + (number of AB) divided by 2 * (total number of individuals)

Therefore,

{2 * (200) + (75)} / 2 (200 +75 +25)

This comes out to be 475/600 = 0.792. Thus, p = 0.792.

Since, q is 1 - p

Then, q = 1 - 0.792 i.e 0.208.