Red colour blindness is due to the lack of pigment

Options

A. Cyanolabe
B. Chlorolabe
C. Erythrolabe
D. None

Answer

### Step-by-Step Solution:

1. **Understanding Red Color Blindness**:
- Red color blindness is a condition where individuals cannot perceive red colors due to the absence of a specific pigment in the retina known as erythrolab.

2. **Role of Pigments in Vision**:
- The retina contains different types of photoreceptor cells called cones and rods. Cones are responsible for color differentiation, while rods are responsible for vision in low light conditions.

3. **Function of Cones**:
- There are three types of cones in the retina, each sensitive to different colors:
- Erythrolab (red)
- Chlorolab (green)
- Cyanolab (blue)
- The absence of erythrolab leads to the inability to perceive red colors.

4. **Genetic Basis of Red Color Blindness**:
- Red color blindness is caused by a mutation in the gene located on the X chromosome. This makes it a sex-linked recessive trait.
- Since it is recessive, an individual must inherit the mutated gene from both parents to express the condition. Males (who have only one X chromosome) are more likely to be affected than females.

5. **Conclusion**:
- In summary, red color blindness occurs due to the lack of the erythrolab pigment in the retina, which is a result of a mutation on the X chromosome.