Hardy Weinberg equation can be used to calculate allele frequencies and genotype frequencies in a population and analyse any changes occurring due to evolution.
The equation is expressed as:
Here p is the frequency of allele ‘A’ and q is the frequency of allele ‘a’.
p2 represents homozygous dominant genotype “AA”.
q2 represents homozygous recessive genotype “aa”.
2pq represents heterozygous genotype “Aa”.
According to the equation, .
If the allele frequencies are known then the gene frequencies can be calculated from the equation if there is no mutation, gene flow, random mating, and selection occurred.
It is just a theoretical approach to predicting gene frequency.
So, if the frequency of one allele is known another allele frequency can be calculated.