Hardy Weinberg Bead Simulation

Students model allele and genotype frequencies with colored beads under two scenarios: random mating and selection against a recessive homozygote.

• See links below for method.

Hardy Weinberg Simulation With Pop Beads - Flipped Lab Videos:

📄 Hardy Weinberg Simulation - Biology Corner: https://www.biologycorner.com/worksheets/hardy_wein_simulation.html

• Start with unequal allele frequencies, for example p = 0.7 and q = 0.3, and test return to equilibrium under random mating.
• Model nonrandom mating by pairing only like genotypes and compare to random pairing.
• Add migration by moving a set number of beads of a specific allele into or out of the class between generations.
• Introduce mutation by converting a small number of T to t or t to T each generation at a fixed rate.
• Simulate genetic drift by repeating Case 1 with small groups and comparing replicate outcomes.

• Supervise use of small beads to prevent choking hazards. Keep beads off the floor to avoid slips.
• Use containers or cups to organize beads and minimize spills.
• Establish clear movement and partner switching rules to prevent crowding or collisions.

• Why can genotype counts fluctuate in Case 1 even if p and q remain stable? (Sampling error and finite population size cause random variation in genotype counts.)
• In Case 2, what happens to p and q when tt individuals do not survive? (q decreases and p increases over generations because selection removes recessive alleles when expressed as tt.)
• In a large population, can selection completely eliminate a lethal recessive allele? (Not easily. As q becomes small, most t alleles are hidden in heterozygotes and selection acts weakly on them. Elimination would require very long time or additional forces like drift or mutation bias.)