Gene for colour blindness in man is located on

Options

A. both X and Y chromosome
B. Y-chromosome only
C. X-chromosome only
D. either X - chromosome or Y- chromosome

Answer

To solve the question regarding the location of the gene for color blindness in humans, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Color Blindness**:
- Color blindness is a condition where individuals have difficulty distinguishing between certain colors, most commonly red and green.

2. **Identifying the Genetic Basis**:
- Color blindness is known to be a genetic condition. It is classified as a sex-linked recessive disorder.

3. **Chromosomal Location**:
- The gene responsible for color blindness is located on the X chromosome. This is similar to other sex-linked disorders, such as hemophilia.

4. **Sex-Linked Inheritance**:
- In females (XX), a colorblind phenotype will occur only if both X chromosomes carry the allele for color blindness. If only one X chromosome carries the allele, the female will be a carrier but not colorblind.
- In males (XY), since they have only one X chromosome, the presence of the allele for color blindness on that chromosome will result in color blindness.

5. **Conclusion**:
- Since the gene for color blindness is located on the X chromosome, the correct answer to the question is that the gene for color blindness in man is located on the X chromosome.

### Final Answer:
- The gene for color blindness in man is located on the **X chromosome**.

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