What is the Hardy-Weiberg principle? How do I use the calculations? What are the limitations?

The Hardy-Weinberg principle is used in population genetics. Population genetics is the study of allele frequencies in populations and how they change over time. There are 2 equation used in the Hardy-Weinberg principle. These are used to find the pecentage of each phenotype or genotype in a population e.g. how many people have blue eyes, how many lizards have allele Ap² + 2pq + q² = 1 --> Used when given information about phenotypes/genotypesp + q = 1 --> Used when given information about allele frequencyp = frequency of allele Aq = frequency of allele ap² = frequency of AA genotypeq² = frequency of aa genotype2pq = frequency of Aa genotypeFor example - If 98 out of 200 individuals in a population express the recessive phenotype, what percent of the population would you predict would be heterozygotes? 98/200 = 0.49 = q2 (using q2 because discussing phenotypes) Sqrt 0.49 = 0.7 = q p + q = 1 p = 1 – 0.7 = 0.3 2pq = 2 x 0.3 x 0.7 = 0.42 42% heterozygotes The 5 key conditions for Hardy Wienberg to work (maintain genetic equilibrium)No mutations so no new alleles Population size is large so there are no genetic bottlenecks Random mating is occurring so alleles are mixed randomly No immigration/emigration so no genes are introduced or lost No selection occurs so no alleles are favoured or eliminated Means all genotypes can survive and reproduce equally well. BUT this not the case in real life