Dihybrid Punnett Squares

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Dihybrid Punnett Squares
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Steps

• 1. Identify the parents genotypes.
• Ex. heterozygous tall, homozygous red flowers.
  TtRR
• 2. Use FOIL to get gamete (sex cell)
  possiblities.
• Ex. TR or tR
• 3. Short cuthow many boxes for the punnett
  square depends on how many possible gametes.

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Example

• TtRR x TtRr
• P1 TR, tR
• P2 TR, Tr, tR, tr

TR Tr tR tr
TTRR TTRr TtRR TtRr
TtRR TtRr ttRR ttRr
TR tR
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Phenotypic ratios

• How many???
• Tall and Red
• Tall and White
• Short and Red
• Short and White