Sex-linked traits are generally

Options

A. Lethal
B. Recessive
C. Dominant
D. Pleiotropic

Explanation

**Step-by-Step Solution:**

1. **Understanding Sex-Linked Traits:**
- Sex-linked traits are associated with genes located on the sex chromosomes (X and Y chromosomes).
- These traits are often linked to the X chromosome because it carries more genes compared to the Y chromosome.

**Hint:** Remember that sex-linked traits are primarily associated with the X chromosome due to its larger size and gene content.

2. **Examples of Sex-Linked Traits:**
- An example of a sex-linked trait is color blindness, which is caused by a mutation on the X chromosome (denoted as \(X^C\)).
- The normal allele is denoted as \(X\), while the disease-causing allele is \(X^C\).

**Hint:** Use color blindness as a classic example to understand how sex-linked traits are inherited.

3. **Inheritance Patterns in Females:**
- Females have two X chromosomes (XX). If they have one normal and one mutated allele (\(X X^C\)), they are carriers but do not express the disease.
- If they have two mutated alleles (\(X^C X^C\)), they will express the disease.

**Hint:** For females, the disease is expressed only if they have two copies of the mutated allele (homozygous condition).

4. **Inheritance Patterns in Males:**
- Males have one X and one Y chromosome (XY). If the X chromosome carries the mutation (\(X^C Y\)), they will express the disease because they have no second X chromosome to mask the effect.

**Hint:** For males, having just one copy of the mutated allele on the X chromosome will result in the expression of the disease.

5. **Conclusion on Dominance:**
- Sex-linked traits are generally recessive. This means that the trait is expressed only when two copies of the mutated allele are present in females or one copy in males.

**Hint:** Recognize that sex-linked traits are typically recessive, meaning they are not expressed in the presence of a normal allele in females.

**Final Answer:**
Sex-linked traits are generally recessive.