Worksheet on incomplete dominance genetics problems with Punnett squares for flower color and hair type.

Let's solve each problem step by step, explaining the concepts of incomplete dominance and how to use Punnett squares.

---

Problem 1:

> In a certain type of flower, color is incompletely dominant. Cross a pure purple flower with a pure white flower. What will be the phenotype of the offspring?

#### Step 1: Understand incomplete dominance
In incomplete dominance, neither allele is completely dominant over the other. The heterozygous genotype results in an intermediate phenotype (a blend of the two).

Let’s assign alleles:
- Let P = purple allele
- Let p = white allele

So:
- PP = purple flower
- pp = white flower
- Pp = lavender (intermediate)

#### Cross: PP × pp

Parent 1: PP → gametes: P, P
Parent 2: pp → gametes: p, p

Now make a Punnett square:

| | P | P |
|-------|-------|-------|
| p | Pp | Pp |
| p | Pp | Pp |

All offspring are Pp, so:

➡️ Offspring phenotype: Lavender (since it's incomplete dominance)

✔ Answer:
- Offspring phenotype: Lavender

---

Problem 2:

> When the genotype is heterozygous, the phenotype is lavender. Use the same letters as above. Cross a lavender flower with a lavender flower.

So now we’re doing: Pp × Pp

Gametes from each parent: P and p

Punnett square:

| | P | p |
|-------|-------|-------|
| P | PP | Pp |
| p | Pp | pp |

#### 2a. Offspring genotypes AND probabilities:

- PP → 1/4 → Purple
- Pp → 2/4 = 1/2 → Lavender
- pp → 1/4 → White

✔ Genotypes and probabilities:
- PP: 25%
- Pp: 50%
- pp: 25%

#### 2b. Offspring phenotypes AND probabilities:

- Purple: 25% (PP)
- Lavender: 50% (Pp)
- White: 25% (pp)

✔ Phenotypes and probabilities:
- Purple: 25%
- Lavender: 50%
- White: 25%

---

Problem 3:

> In humans, you can have curly hair, straight hair, or wavy hair. This is incomplete dominance.

Let’s define:
- C = curly hair allele
- c = straight hair allele
- Cc = wavy hair (intermediate phenotype)

#### Part 1: Cross a wavy-haired person with a straight-haired person

Genotypes:
- Wavy: Cc
- Straight: cc

Gametes:
- Cc → C, c
- cc → c, c

Punnett square:

| | C | c |
|-------|-------|-------|
| c | Cc | cc |
| c | Cc | cc |

Offspring:
- Cc → wavy hair → 2/4 = 50%
- cc → straight hair → 2/4 = 50%

✔ Part 1: Phenotypes and probabilities
- Wavy hair: 50%
- Straight hair: 50%

---

#### Part 2: Cross a wavy-haired person with a wavy-haired person

Genotypes: Cc × Cc

Gametes: C, c from each parent

Punnett square:

| | C | c |
|-------|-------|-------|
| C | CC | Cc |
| c | Cc | cc |

Offspring:
- CC → curly hair → 1/4 = 25%
- Cc → wavy hair → 2/4 = 50%
- cc → straight hair → 1/4 = 25%

✔ Part 2: Phenotypes and probabilities
- Curly hair: 25%
- Wavy hair: 50%
- Straight hair: 25%

---

✔ Final Answers Summary:

---

#### Problem 1:
- Offspring phenotype: Lavender

---

#### Problem 2:
2a. Genotypes and probabilities:
- PP: 25%
- Pp: 50%
- pp: 25%

2b. Phenotypes and probabilities:
- Purple: 25%
- Lavender: 50%
- White: 25%

---

#### Problem 3:

Part 1: Wavy × Straight (Cc × cc)
- Phenotypes:
- Wavy: 50%
- Straight: 50%

Part 2: Wavy × Wavy (Cc × Cc)
- Phenotypes:
- Curly: 25%
- Wavy: 50%
- Straight: 25%

---

You can now fill in the Punnett squares on your worksheet accordingly. Let me know if you'd like a visual version!