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Genetics

Punnett Square Builder

Build a cross and predict genotype and phenotype ratios.

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Interactive Punnett Square

Choose alleles for each parent. B = Brown eyes (dominant), b = Blue eyes (recessive). Ratios update live.

Parent 1
= Bb
Parent 2
= bb
bb
BBbBb
bbbbb
Genotype ratio
  • Bb2/4 (50%)
  • bb2/4 (50%)
Phenotype ratio
  • Brown eyes (dominant)50%
  • Blue eyes (recessive)50%
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