In Hardy Weinberg equation, the frequency of heterogygous individuals is represented by :

q2 p2 2pq pq

2pq

According to the Hardy Weinberg law, the allele and genotype frequencies in a population remain constant in the absence of factors responsible for evolution.  $\bullet$ It states that the sum of all genotype frequencies can be represented as the binomial expansion of the square of the sum of $p$ and $q$. $\bullet$ This sum is equal to one : (p+q)2 = p2 + $2pq$ + q2 = $1$.  $\bullet$ "p" is the frequency of the dominant allele, $\bullet$ "q" is the frequency of the recessive allele.  $\bullet$ "2pq" is the frequency of heterozygotes in the population.