Conditions Required for Hardy-Weinberg Equilibrium (College Board AP® Biology)

Conditions for Hardy-Weinberg Equilibrium

• The Hardy-Weinberg principle states that if certain conditions are met then the allele frequencies of a gene within a population will not change from one generation to the next

• There are seven conditions or assumptions that must be met for the Hardy-Weinberg principle to hold true

• The Hardy-Weinberg equation allows for the calculation of allele and genotype frequencies within populations

• It also allows for predictions to be made about how these frequencies will change in future generations

Conditions for Hardy-Weinberg equilibrium

• For the Hardy-Weinberg principle to be correctly applied to a population a series of conditions, or assumptions, need to be met

  • Organisms are diploid

  • Organisms reproduce by sexual reproduction only

  • There is no overlap between generations, i.e. parents do not mate with offspring

  • Mating is random

  • The population is large

  • There is no migration, mutation, or selection

    • This would mean no individuals entering the population (immigration) or leaving (emigration)

    • Selection refers to both natural and artificial selection

  • Allele frequencies are equal in both sexes

• The Hardy-Weinberg principle can be useful when building models and making predictions, but the assumptions listed are very rarely, if ever, all present in nature

• Despite this, the Hardy-Weinberg equilibrium concept can provide a useful null hypothesis when evaluating the effects of genetic changes