7.5.A—Describe the conditions under which allele and genotype frequencies will change in populations

Describe the conditions under which allele and genotype frequencies will change in populations.

• The Hardy–Weinberg Equilibrium is a model for describing and predicting allele frequencies in a non-evolving population. Conditions for a population or an allele to be in Hardy–Weinberg equilibrium are:
  • i. A large population size
  • ii. No migration
  • iii. No new mutations
  • iv. Random mating
  • v. No natural selection These conditions are never met, but they provide a valuable null hypothesis.
• Allele frequencies in a nonevolving population can be calculated from genotype frequencies. RELEV ANT EQUATIONS Hardy–Weinberg Equation— ++ =pp qq2 122 pq 1+= , where: p = frequency of allele 1 in the population q = frequency of allele 2 in the population