Q. At a particular locus, frequency of allele is and that of allele a is . What would be the frequency of heterozygotes in a random mating population at equilibrium?

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Solution:

In a stable population, for a gene with two alleles, 'A' (dominant) and 'a' (recessive), if the frequency of 'A' is and the frequency of 'a' is q, then the frequencies of the three possible genotypes (AA, Aa and aa) can be expressed by the Hardy-Weinberg equation:

where = Frequency of (homozygous dominant) individuals
= Frequency of (homozygous recessive) individuals
= Frequency of Aa (heterozygous) individuals
so, and (given)
(frequency of heterozygote)