Genes for colour blindness in humans are carried by

Options

A. Mother
B. Father
C. Both
D. Abnormal sex

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Trait**: The first step is to recognize that color blindness in humans is a genetic trait. Specifically, it is associated with the inability to perceive certain colors, which is primarily due to mutations in specific genes.

2. **Identifying the Chromosome**: Color blindness is linked to the X chromosome. Humans have two sex chromosomes: females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

3. **Inheritance Pattern**: Since color blindness is an X-linked trait, it can be inherited from both parents. Males inherit their single X chromosome from their mother, while females inherit one X chromosome from each parent.

4. **Recessive Nature of the Trait**: The allele for red-green color blindness is recessive. This means that for a female to be color blind, she must have two copies of the mutant allele (homozygous recessive). In contrast, a male only needs one copy of the mutant allele (hemizygous) to express the trait.

5. **Carrier Status**: Females with one normal allele and one mutant allele are considered carriers. They do not exhibit color blindness but can pass the mutant allele to their offspring.

6. **Conclusion**: Therefore, the genes for color blindness are carried by both the mother and the father. The correct answer to the question is that both parents contribute to the inheritance of color blindness due to the X-linked nature of the trait.

**Final Answer**: Genes for color blindness in humans are carried by both mother and father.

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