Worksheet on incomplete dominance and codominance featuring genetics problems about cat fur color and human hair type.

Problem Analysis:

The worksheet involves understanding codominance and incomplete dominance in genetics. Let's solve each problem step by step.

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Problem 1: Cat Fur Color (Codominance)

#### Given:
- Cat fur color is determined by codominance.
- Allele for tan fur: \( T \)
- Allele for black fur: \( B \)
- Heterozygous condition (\( TB \)): results in a tabby cat (tan and black spots).
- A tan cat (\( TT \)) is crossed with a tabby cat (\( TB \)).

#### Task:
1. Draw the Punnett square.
2. Identify the genotypes and phenotypes of their offspring.

#### Solution:
1. Genotypes of Parents:
- Tan cat: \( TT \)
- Tabby cat: \( TB \)

2. Punnett Square:
- Parent 1 (\( TT \)): Gametes are \( T \) and \( T \).
- Parent 2 (\( TB \)): Gametes are \( T \) and \( B \).

| | \( T \) | \( T \) |
|-----|---------|---------|
| \( T \) | \( TT \) | \( TT \) |
| \( B \) | \( TB \) | \( TB \) |

3. Offspring Genotypes and Phenotypes:
- \( TT \): Tan fur (2 offspring)
- \( TB \): Tabby fur (2 offspring)

Summary:
- Genotypes: \( TT, TT, TB, TB \)
- Phenotypes: 2 tan cats, 2 tabby cats

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Problem 2: Probability of Offspring from Two Tabby Cats

#### Given:
- Two tabby cats (\( TB \)) are crossed with each other.

#### Task:
1. What is the likelihood that they will have a tabby kitten?
2. What is the likelihood that they will have a black kitten?

#### Solution:
1. Punnett Square:
- Both parents are \( TB \).
- Gametes from each parent: \( T \) and \( B \).

| | \( T \) | \( B \) |
|-----|---------|---------|
| \( T \) | \( TT \) | \( TB \) |
| \( B \) | \( TB \) | \( BB \) |

2. Offspring Genotypes and Phenotypes:
- \( TT \): Tan fur
- \( TB \): Tabby fur
- \( BB \): Black fur

3. Probability Calculation:
- Total possible offspring: 4
- Tabby kittens (\( TB \)): 2 out of 4 → Probability = \( \frac{2}{4} = \frac{1}{2} = 50\% \)
- Black kittens (\( BB \)): 1 out of 4 → Probability = \( \frac{1}{4} = 25\% \)

Summary:
- Likelihood of a tabby kitten: 50%
- Likelihood of a black kitten: 25%

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Problem 3: Human Hair Type (Incomplete Dominance)

#### Given:
- Hair type is determined by incomplete dominance.
- Curly hair allele: \( C \)
- Straight hair allele: \( S \)
- Heterozygotes (\( CS \)): Wavy hair.

#### Task:
1. If a person with wavy hair (\( CS \)) has a baby with a person with straight hair (\( SS \)), what would occur?
2. Draw the Punnett square and identify the genotypes and phenotypes of their offspring.

#### Solution:
1. Genotypes of Parents:
- Wavy-haired parent: \( CS \)
- Straight-haired parent: \( SS \)

2. Punnett Square:
- Parent 1 (\( CS \)): Gametes are \( C \) and \( S \).
- Parent 2 (\( SS \)): Gametes are \( S \) and \( S \).

| | \( S \) | \( S \) |
|-----|---------|---------|
| \( C \) | \( CS \) | \( CS \) |
| \( S \) | \( SS \) | \( SS \) |

3. Offspring Genotypes and Phenotypes:
- \( CS \): Wavy hair (2 offspring)
- \( SS \): Straight hair (2 offspring)

Summary:
- Genotypes: \( CS, CS, SS, SS \)
- Phenotypes: 2 wavy-haired babies, 2 straight-haired babies

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Problem 4: Probability of Offspring from Two Wavy-Haired People

#### Given:
- Two people with wavy hair (\( CS \)) have a baby together.

#### Task:
1. What is the likelihood that they will have a curly-haired baby?
2. What is the likelihood that they will have a straight-haired baby?

#### Solution:
1. Punnett Square:
- Both parents are \( CS \).
- Gametes from each parent: \( C \) and \( S \).

| | \( C \) | \( S \) |
|-----|---------|---------|
| \( C \) | \( CC \) | \( CS \) |
| \( S \) | \( CS \) | \( SS \) |

2. Offspring Genotypes and Phenotypes:
- \( CC \): Curly hair
- \( CS \): Wavy hair
- \( SS \): Straight hair

3. Probability Calculation:
- Total possible offspring: 4
- Curly-haired babies (\( CC \)): 1 out of 4 → Probability = \( \frac{1}{4} = 25\% \)
- Straight-haired babies (\( SS \)): 1 out of 4 → Probability = \( \frac{1}{4} = 25\% \)

Summary:
- Likelihood of a curly-haired baby: 25%
- Likelihood of a straight-haired baby: 25%

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Final Answers:

1. Cat Fur Color:
- Genotypes: \( TT, TT, TB, TB \)
- Phenotypes: 2 tan cats, 2 tabby cats

2. Tabby Cats Crossed:
- Likelihood of a tabby kitten: \( \boxed{50\%} \)
- Likelihood of a black kitten: \( \boxed{25\%} \)

3. Wavy-Haired Person and Straight-Haired Person:
- Genotypes: \( CS, CS, SS, SS \)
- Phenotypes: 2 wavy-haired babies, 2 straight-haired babies

4. Two Wavy-Haired People:
- Likelihood of a curly-haired baby: \( \boxed{25\%} \)
- Likelihood of a straight-haired baby: \( \boxed{25\%} \)