Frequency Calculations

Allele Frequencies = Genetic Variation in a Population 

Genotype Frequencies = How Variation is Distributed in the Population

Alleles

Text

Genotypes

Text

Hardy-Weinberg Equilibrium

• A model in which allele frequencies do not change across generations, and genotype frequencies can be predicted from allele frequencies.  If conditions change, "evolution" will occur.  
• NO MUTATION
• NO SELECTION AMONG GENOTYPES
• NO GENE FLOW
• POPULATION SIZE IS INFINITE
• MATING IS RANDOM

Hardy-Weinberg

Non-Factors

• Migration into or out of population
• Selective mating
• Terminal Traits
• Genetic Drift
• Natural Selection

Case 1: normal

Case 2: aa dies - Albino

Case 3: aa dies, AA coin flip  - sickle cell