Explanation

Hardy-Weinberg's principle states that "gene frequency in a population remains stable and constant from generation to generation".

Hardy and Weinberg used mathematics to describe:

Equilibrium population (p = frequency of A, q = frequency of a, so p + q = 1)

p2 + 2pq + q2 = 1.

Where p and q are frequency of the dominant and recessive allele respectively.

This equation can also be used to calculate the genotypic frequencies in a population at equilibrium.

p2= homozygous dominant frequency

q2= homozygous recessive frequency

2pq= heterozygous frequency