Hardy-Weinberg Principle and Allele Frequencies

Gene Pool

Total alleles in a population's gene pool.

Genotypic Frequency

Proportion of genotypes in a population.

Allele Frequency

Proportion of a specific allele in a population.

Total Alleles Calculation

Total alleles = 2 x number of individuals.

Evolution Requirement

Gene frequencies must change over time.

Hardy-Weinberg Principle

Model for no change in gene pool.

Assumptions of Hardy-Weinberg

Large population, random mating, no mutations.

Albinism

Genetically inherited trait expressed in homozygous recessives.

Homozygous Recessive Frequency

Frequency of individuals with genotype aa.

Hardy-Weinberg Equation

p² + 2pq + q² = 1.

Frequency of Homozygous Recessive

q² represents frequency of aa individuals.

Albinism Frequency in North America

1 in 20,000 individuals have albinism.

Calculating q²

q² = 1/20,000 = 0.00005.

Calculating q

q = √(q²) = 0.007.

Frequency of Recessive Allele

Frequency of allele a is 0.007.

Calculating p

p = 1 - q = 0.993.

Frequency of Dominant Allele

Frequency of allele A is 0.993.

Genotype Frequencies Calculation

Use p and q in Hardy-Weinberg equation.

Homozygous Dominant Frequency

p² = 0.986 or 98.6%.

Heterozygous Frequency

2pq = 0.014 or 1.4%.

Predicted Homozygous Recessive Frequency

q² = 0.00005 or 0.005%.