Dihybrid Inheritance

• Setting up a Punnett square

  1. Set up a 2 by 2 Punnett square

  2. Write the alleles for parent 1 on the left side

  3. Write the alleles from parent 2 above the Punnett square

  4. Fill the squares for parent 1

  5. Fill the squares for parent 2
• Dihybrid inheritance


  Pertains to the inheritance of two traits at a time
• Mendel's experiments


  • Selected pure-breeding pea plants with round and yellow seeds
  • Selected pure-breeding plants with wrinkled and green seeds
  • Cross-pollinated to get first filial (F1) generation with round yellow seeds
• Mendel's observations


  1. The genes for seed shape are inherited separately from the genes for seed color

  2. This is Mendel's Law of Independent Assortment of Genes

  3. The inheritance of seed shape does not influence the inheritance of seed color, because the two are independent of each other

  4. The law of independent assortment of genes also implies that traits for two different characters pair up independently

  5. Round and yellow or wrinkled and green do not always go together

  6. Round seeds may have green color, and wrinkled seeds may have yellow color