What is allele frequency?
Allele frequency is the percentage of appearances of an allele in the genotypes of a given population (compared to the other alleles of the studied gene). For example, in the ABO blood system there are three alleles (IA, IB and i). Considering a group of three persons, one with genotype IAi, other IAIB and other ii, the frequency of the allele IA in this “population” is 2/6, the frequency of the allele IB is 1/6 and the frequency of the allele i is 3/6.
