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;
$\text{frequency }\left(\right. \text{A} \left.\right) \, = \, p$
frequency $\text{}\left(\right. \text{a} \left.\right) \, = \, q$
And, $p \, + \, q \, = \text{ 1}$ .
If mating is random, then new individuals will have:
$\text{}$ frequency $\text{} \left(\right. \text{AA} \left.\right) \, = \, p^{2}$ for the AA homozygotes in the population,
$\text{}$ frequency $\text{} \left(\right. \text{aa} \left.\right) \, = \, q^{2}$ for the aa homozygotes, and
$\text{}$ frequency $\text{} \left(\right. \text{Aa} \left.\right) \, = \text{ 2} p q$ for the Aa heterozygotes.