Basic Population Genetics

Abstract

Hardy (the English mathematician) and W. Weinberg (the German physician) independently worked out the mathematical basis of population genetics in 1908 (Hardy, 1908). Their formula predicts the expected genotype frequencies using the allele frequencies in a diploid Mendelian population. They were concerned with questions like "what happens to the frequencies of alleles in a population over time?" and "would you expect to see alleles disappear or become more frequent over time?" Hardy and Weinberg showed in the following manner that if the population is very large and random mating is taking place, allele frequencies remain unchanged (or in equilibrium) over time unless some other factors intervene. If the frequencies of allele A and a (of a biallelic locus) are p and q, then (p + q) = 1. This means (p + q) 2 = 1 too. It is also correct that (p + q) 2 = p 2 + 2pq +q 2 = 1. In this formula, p 2