Hardy-Weinberg principle

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In genetics, the Hardy–Weinberg principle states that gene frequency remains constant across generations (no genetic drift) unless a force causes phenomena such as gene flow.

In an example of two alleles, 'A' and 'a', random frequency is based on the binomial expansion

Thus the following distributions are examples of equilibrium:

  • AA is 100%; Aa and aa are both 0%
  • aa is 100%; Aa and AA are both 0%
  • Aa is 50%; AA and aa are both 25%
  • Aa is 4/9; AA is 4/9 and aa is 1/9
  • Aa is 4/9; AA is 1/9 and aa is 4/9

Testing for Hardy–Weinberg equilibrium is studies of associations between genetic polymorphisms and diseases is controversial.[1][2] Studies having violations of equilibrium may have less stable results and may tend to have more positive results.[2]

References