Question : How is Hardy-Weinberg’s expression “(p2 + 2pq+q 2 ) = 1”derived?
The correct answer is – (a) Sum Total of All the Allele Frequencies is 1: Let there be two alleles A and a in a population. The frequencies of alleles A and a are ‘p’ and ‘q’ respectively. The frequency of AA individuals in a population is p 2 and it can be explained that the probability that an allele A with a frequency of p would appear on both the chromosomes of a diploid individual is simply the product of the probabilities, i.e., p2
Similarly, the frequency of aa is q2
and that of Aa is pq.
3
4
p
2
+ 2pq+q 2 = 1,where p 2
represents the frequency of homozygous
dominant genotype, 2pq represents the frequency of the heterozygous
genotype and q 2 represents the frequency of the homozygous
recessive.
