======Hardy Weinberg Bead Simulation======


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**Materials: **{{$demo.materials_description}}\\
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**Alternative titles:** Random Mating and Selection Model
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====Summary====                   
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====Procedure====  
  * See links below for method.



====Links==== 
Hardy Weinberg Simulation With Pop Beads - Flipped Lab Videos: 
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📄 Hardy Weinberg Simulation - Biology Corner: [[https://www.biologycorner.com/worksheets/hardy_wein_simulation.html]]\\


====Variations====
  * 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.



====Safety Precautions====
  * 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.




====Questions to Consider====
  * 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.)