50 Genotypes And Phenotypes Worksheet Answers - Free Printable

Let’s go step by step through each Punnett square. We’ll fill in the boxes, count the genotypes, and then figure out the phenotypes.

Remember:
- Dominant allele = capital letter (A) → shows up even if only one copy is present.
- Recessive allele = lowercase letter (a) → only shows up if two copies are present (aa).
- Genotype = genetic makeup (like AA, Aa, aa)
- Phenotype = what you see (dominant or recessive trait)

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Section 1: Crosses with one homozygous dominant parent

#### Cross 1: AA x AA

Parent 1 (top): A and A
Parent 2 (side): A and A

Fill in the squares:

| | A | A |
|---|---|---|
| A | AA | AA |
| A | AA | AA |

All offspring = AA

→ Offspring Genotypes:
AA _4_ Aa _0_ aa _0_

→ Offspring Phenotypes:
Dominant _4_
Recessive _0_

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#### Cross 2: AA x Aa

Parent 1 (top): A and A
Parent 2 (side): A and a

Fill in:

| | A | A |
|---|---|---|
| A | AA | AA |
| a | Aa | Aa |

Offspring: 2 AA, 2 Aa

→ Offspring Genotypes:
AA _2_ Aa _2_ aa _0_

→ Offspring Phenotypes:
Dominant _4_ (both AA and Aa show dominant trait)
Recessive _0_

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#### Cross 3: AA x aa

Parent 1 (top): A and A
Parent 2 (side): a and a

Fill in:

| | A | A |
|---|---|---|
| a | Aa | Aa |
| a | Aa | Aa |

All offspring = Aa

→ Offspring Genotypes:
AA _0_ Aa _4_ aa _0_

→ Offspring Phenotypes:
Dominant _4_
Recessive _0_

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Section 2: Crosses with one heterozygous parent

#### Cross 4: Aa x AA

Parent 1 (top): A and a
Parent 2 (side): A and A

Fill in:

| | A | a |
|---|---|---|
| A | AA | Aa |
| A | AA | Aa |

Offspring: 2 AA, 2 Aa

→ Offspring Genotypes:
AA _2_ Aa _2_ aa _0_

→ Offspring Phenotypes:
Dominant _4_
Recessive _0_

*(Note: This is same as Cross 2 — just flipped parents)*

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#### Cross 5: Aa x Aa

Parent 1 (top): A and a
Parent 2 (side): A and a

Fill in:

| | A | a |
|---|---|---|
| A | AA | Aa |
| a | Aa | aa |

Offspring: 1 AA, 2 Aa, 1 aa

→ Offspring Genotypes:
AA _1_ Aa _2_ aa _1_

→ Offspring Phenotypes:
Dominant _3_ (AA + Aa)
Recessive _1_ (aa)

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#### Cross 6: Aa x aa

Parent 1 (top): A and a
Parent 2 (side): a and a

Fill in:

| | A | a |
|---|---|---|
| a | Aa | aa |
| a | Aa | aa |

Offspring: 2 Aa, 2 aa

→ Offspring Genotypes:
AA _0_ Aa _2_ aa _2_

→ Offspring Phenotypes:
Dominant _2_ (Aa)
Recessive _2_ (aa)

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Section 3: Crosses with one homozygous recessive parent

#### Cross 7: aa x AA

Parent 1 (top): a and a
Parent 2 (side): A and A

Fill in:

| | a | a |
|---|---|---|
| A | Aa | Aa |
| A | Aa | Aa |

All offspring = Aa

→ Offspring Genotypes:
AA _0_ Aa _4_ aa _0_

→ Offspring Phenotypes:
Dominant _4_
Recessive _0_

*(Same as Cross 3 — flipped parents)*

---

#### Cross 8: aa x Aa

Parent 1 (top): a and a
Parent 2 (side): A and a

Fill in:

| | a | a |
|---|---|---|
| A | Aa | Aa |
| a | aa | aa |

Offspring: 2 Aa, 2 aa

→ Offspring Genotypes:
AA _0_ Aa _2_ aa _2_

→ Offspring Phenotypes:
Dominant _2_
Recessive _2_

*(Same as Cross 6 — flipped parents)*

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#### Cross 9: aa x aa

Parent 1 (top): a and a
Parent 2 (side): a and a

Fill in:

| | a | a |
|---|---|---|
| a | aa | aa |
| a | aa | aa |

All offspring = aa

→ Offspring Genotypes:
AA _0_ Aa _0_ aa _4_

→ Offspring Phenotypes:
Dominant _0_
Recessive _4_

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Final Answer:

Cross 1 (AA x AA):
Genotypes: AA=4, Aa=0, aa=0
Phenotypes: Dominant=4, Recessive=0

Cross 2 (AA x Aa):
Genotypes: AA=2, Aa=2, aa=0
Phenotypes: Dominant=4, Recessive=0

Cross 3 (AA x aa):
Genotypes: AA=0, Aa=4, aa=0
Phenotypes: Dominant=4, Recessive=0

Cross 4 (Aa x AA):
Genotypes: AA=2, Aa=2, aa=0
Phenotypes: Dominant=4, Recessive=0

Cross 5 (Aa x Aa):
Genotypes: AA=1, Aa=2, aa=1
Phenotypes: Dominant=3, Recessive=1

Cross 6 (Aa x aa):
Genotypes: AA=0, Aa=2, aa=2
Phenotypes: Dominant=2, Recessive=2

Cross 7 (aa x AA):
Genotypes: AA=0, Aa=4, aa=0
Phenotypes: Dominant=4, Recessive=0

Cross 8 (aa x Aa):
Genotypes: AA=0, Aa=2, aa=2
Phenotypes: Dominant=2, Recessive=2

Cross 9 (aa x aa):
Genotypes: AA=0, Aa=0, aa=4
Phenotypes: Dominant=0, Recessive=4