3.7.2 Populations

• A population is a group of organisms of the same species living in the same area at the same time, that can potentially interbreed.
• The gene pool is the total number of alleles that are present in a population.
• Allele Frequency: The proportion of a specific allele within the gene pool.
• The Hardy-Weinberg Equation can be used to estimate the frequency of alleles in a population and to see whether a change in allele frequency is occurring in a population over time.
• The Hardy-Weinberg principle assumes a population is in genetic equilibrium (no evolution occurring) under these conditions:

  1. No mutations occur.

  2. Population is large (no genetic drift).

  3. Random mating.

  4. No migration (gene flow).

  5. No natural selection.
• The Hardy-Weinberg equation for allele frequencies: p + q = 1

  • p : Frequency of the dominant allele.
  • q : Frequency of the recessive allele.
• The Hardy-Weinberg equation for genotype frequencies: p^2 + 2pq + q^2 = 1

  • p^2 : Proportion of homozygous dominant individuals.
  • 2pq : Proportion of heterozygous individuals.
  • q^2 : Proportion of homozygous recessive individuals.