 The Hardy-Weinberg principle, discovered independently by G.H. Hardy and W. Weinberg in 1908, is one of the simplest and most important principles in population genetics (Hardy 1908, Weinberg 1908). To illustrate the principle, consider a large population of sexually reproducing organisms. The organisms are diploids, meaning that they contain two copies of each chromosome, one received from each parent. The gametes they produce are haploid, meaning that they contain only one of each chromosome pair. During sexual fusion, two haploid gametes fuse to form a diploid zygote, which then grows and develops into an adult organism. Most multi-celled animals and many plants have a lifecycle of this sort.