Hardy-Weinberg Equilibrium

What Is The Hardy-Weinberg Equilibrium?

• A population’s allele and genotype frequencies are constant unless there is some type of evolutionary force acting upon them

• There are 5 conditions a population must meet to be in Hardy-Weinberg Equilibrium

  • No (Natural) Selection

    • Neither trait is being chosen against (such as killing off certain people with certain traits, think of that Logan Paul movie)

  • No Mutations

    • Offspring do not carry mutations from their parents

  • No Migration

    • Nobody goes in, nobody goes out

  • Large Population

    • Smaller population are more prone to Genetic Drifting

    • What Are Genetic Drifts? See Genetic Drift notes

  • Random Mating

    • People mate without any specific choice

    • Random mating

• Due to how unreliable these five conditions are (i.e. it’s impossible to even meet all five conditions IRL) there are two equations we can use instead

p + q = 1 - ALLELE FREQUENCY

• p represents the dominant allele frequency

• q represents the recessive allele frequency

  • Side notes:

    • p and q DO NOT need to equal to each other

    • q can be larger than p despite p being the “dominant allele”

      • Just because it’s dominant does not mean it appears more often, it just shows better between a recessive and dominant allele

p² + 2pq + q² = 1 - GENOTYPE FREQUENCY

• p² is the homozygous dominant frequency

• 2pq is the heterozygous frequency

• q² is the homozygous recessive frequency

• The video below has an example at the end that walks you through the entire process of solving this equation. It’s not easy, so please watch it thoroughly