In cats, the allele for short hair is dominant to that for long hair. A long-haired male cat mates with a homozygous short-haired female cat. What is the expected appearance of hair in their progeny?

Options

A. 100% short-haired
B. 100% long-haired
C. 50% long-haired and 50% short-haired
D. 75% short-haired and 25% long-haired

Answer

To solve the problem, we need to understand the genetics involved in the inheritance of hair types in cats. Let's break it down step by step.

### Step 1: Identify the Alleles
- The allele for short hair is dominant, represented by **S** (capital S).
- The allele for long hair is recessive, represented by **s** (small s).

### Step 2: Determine the Genotypes of the Parents
- The long-haired male cat has the genotype **ss** (since it expresses the recessive trait).
- The homozygous short-haired female cat has the genotype **SS** (since it expresses the dominant trait and is homozygous).

### Step 3: Set Up the Punnett Square
- We will set up a Punnett square to determine the genotypes of the offspring.
- The male cat contributes **s** (from ss), and the female cat contributes **S** (from SS).

| | S | S |
|-------|-----|-----|
| **s** | Ss | Ss |
| **s** | Ss | Ss |

### Step 4: Analyze the Offspring Genotypes
- From the Punnett square, we see that all offspring will have the genotype **Ss**.

### Step 5: Determine the Phenotypes of the Offspring
- Since **S** (short hair) is dominant over **s** (long hair), all offspring with the genotype **Ss** will exhibit the short-haired phenotype.

### Conclusion
- Therefore, the expected appearance of hair in their progeny will be **100% short hair**.

### Final Answer
The expected appearance of hair in their progeny is **100% short hair**.

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