Polydactyly in man is due to

Options

A. Autosomal recessive allel
B. Autosomal dominant allele
C. Sex linked recessive allele
D. Sex linked dominant allele.

Answer

**Step-by-Step Solution:**

1. **Understanding Polydactyly**:
- Polydactyly is a genetic condition characterized by the presence of more than five fingers or toes on a hand or foot.

2. **Identifying the Genetic Basis**:
- The question asks about the genetic basis of polydactyly in humans. This involves understanding whether the trait is linked to autosomal chromosomes or sex chromosomes and whether it is dominant or recessive.

3. **Explaining Genetic Terms**:
- **Autosomal**: Refers to genes located on non-sex chromosomes (22 pairs of autosomal chromosomes in humans).
- **Sex-linked**: Refers to genes located on sex chromosomes (X and Y chromosomes).
- **Dominant**: A trait that can manifest with just one copy of the allele (mutation).
- **Recessive**: A trait that requires two copies of the allele (mutation) to manifest.

4. **Determining the Type of Allele for Polydactyly**:
- Since polydactyly can occur with just one mutated allele, it indicates that it is a dominant trait.
- The genes responsible for polydactyly are located on the autosomal chromosomes, not on the sex chromosomes.

5. **Conclusion**:
- Based on the above analysis, polydactyly in humans is due to an **autosomal dominant allele**.

**Final Answer**: Polydactyly in man is due to **autosomal dominant allele**.

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