Introduction
Hardy, Weinberg and Castle determined that the frequencies of alleles and genotypes in a
population remain the same over time, given that certain assumptions are met:
• Organisms are diploid
• Generations are non-overlapping
• Population must be large
• No immigration or emigration
• No mutation in the gene of interest
• No natural selection occurs (individuals reproduce at equal rates)
• Mating is random
Overview
How to solve Hardy-Weinberg Problems:
1. Determine the alleles.
1. Frequency of the dominant allele is designated as 'p'
2. Frequency of the recessive allele is designated as 'q'
2. Allelic Frequency Rule (Frequency of a SINGLE ALLELE in the population):
p + q = 1
3. Genotype Frequency Rule (Frequency of a GENOTYPE in the population):
(p+q) (p+q) = 1
Simplify this statement using the FOIL rule:B p2+ pq + pq +q2= 1
p2+ 2pq + q2= 1
p2= frequency of homozygous dominant genotype
2pq = frequency of heterozygous genotype
q2= frequency of homozygous recessive genotype
Penguin Prof Helpful Hints: Solving Hardy-Weinberg Problems
Penguin Prof Helpful Hints: Solving Hardy-Weinberg Problems Page 1
