Q14 of 40 Page 1

What does the following equation represent? Explain.

p2 + 2 pq + q2 = 1


When a population is in Hardy-Weinberg Equilibrium, the genotypic frequencies of the population are represented by the given equation p2 + 2 pq + q2 = 1.


In a diploid, p and q represent the frequency of allele A and allele a. The frequency of AA individuals in a population is p2, of aa individuals is q2 and of Aa individuals is 2pq. The sum total of all allelic frequencies is 1. Hence, p2 + 2 pq + q2 = 1, which is a binomial expansion of (p+q)2.


According to Hardy-Weinberg Principle, the allele frequencies in a population are stable and are constant from generation to generation. However, factors like genetic drift, gene flow, mutation, natural selection and genetic recombination, affect the Hardy-Weinberg equilibrium.


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