Multiple alleles control inheritance of

Options

A. Colour blindness
B. Sickle cell anaemia
C. Blood groups
D. Phenylketonuria

Answer

**Step-by-Step Solution:**

1. **Understanding Multiple Alleles**:
- Multiple alleles refer to a situation where a gene has more than two alternative forms (alleles). This means that for a particular trait, there can be several variations that can exist within a population.

2. **Analyzing the Options**:
- **Option A: Colorblindness**: This is a sex-linked genetic disorder, primarily associated with the X chromosome. It does not involve multiple alleles, as it is controlled by a single gene with two alleles (normal vision and colorblindness).

- **Option B: Sickle Cell Anemia**: This is an autosomal recessive disorder caused by a mutation in the hemoglobin gene. It is not controlled by multiple alleles but rather by a single gene with two alleles (normal hemoglobin and sickle hemoglobin).

- **Option C: Blood Groups**: The ABO blood group system is controlled by the I gene, which has three alleles: Ia, Ib, and i. This is a classic example of multiple alleles in humans, as these alleles determine the different blood types (A, B, AB, and O).

- **Option D: Phenylketonuria (PKU)**: This is also an autosomal recessive disorder caused by a mutation in the gene that helps break down phenylalanine. It does not involve multiple alleles, as it is controlled by a single gene with two alleles (normal and mutant).

3. **Conclusion**:
- Based on the analysis of the options, the only condition that is controlled by multiple alleles is the ABO blood group system. Therefore, the correct answer is **Option C: Blood Groups**.

---