Question

According to Hardy-Weinberg’s principle, if allele one is denoted as ‘A’ and allele two as ‘a’ and their frequencies are denoted by p and q, and if random mating occurs. The frequency of heterozygous individual would be:

• A. 2pq
• B. $q^2$
• C. pq
• D. $p^2$

Answer 1

Answer: (A)

Hardy-Weinberg’s principle states that the allele frequency of a population remains constant from generation to generation unless specific disturbing influences are introduced. This is called genotype equilibrium.
A single locus with two alleles: allele one is denoted as ‘A’ and allele two as ‘a’ and their frequencies are denoted by p and q;
$\text{frequency }(\text{A})=p$
frequency $(\text{a})=q$
And, $p+q=\text{ 1}$ .
If mating is random, then new individuals will have:
frequency $(\text{AA})=p^2$ for the AA homozygotes in the population,
frequency $(\text{aa})=q^2$ for the aa homozygotes, and
frequency $(\text{Aa})=\text{ 2}pq$ for the Aa heterozygotes.