4.12: Hardy-Weinberg Equation to Test for Evolution
- Page ID
- 62240
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The Hardy-Weinberg principle is a mathematical model used to describe the equilibrium of two alleles in a population in the absence of evolutionary forces. This model was derived independently by G.H. Hardy and Wilhelm Weinberg. It states that the allele and genotype frequencies across a population will remain constant across generations in the absence of evolutionary forces. This equilibrium makes several assumptions in order to be true:
- An infinitely large population size
- The organism involved is diploid
- The organism only reproduces sexually
- There are no overlapping generations
- Mating is random
- Allele frequencies equal in both genders
- Absence of migration, mutation or selection
As we can see, many items in the list above cannot be controlled for but it allows for us to make a comparison in situations where expected evolutionary forces come into play (selection, mutation, etc.).
This is important because the equation shows mathematical evidence for evolution. If the frequencies stay the same each generation, then equilibrium has occurred and evolution has NOT occurred. However, if the frequencies change at all, then equilibrium has been disproven, and therefore evolution HAS occurred.