In case of ABO blood grop allele `I^(A)and I^(B)` if present together then-

Options

A. Only `I^(A)` allele expresses
B. Only `I^(B)` allele expresses
C. Both `I^(A) and I^(B)` alleles express
D. None of these

Answer

To solve the question regarding the ABO blood group alleles \( I^A \) and \( I^B \) when present together, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the ABO Blood Group System**:
- The ABO blood group system is controlled by three alleles: \( I^A \), \( I^B \), and \( i \) (where \( i \) is the recessive allele).
- The alleles \( I^A \) and \( I^B \) are both dominant over the recessive allele \( i \).

2. **Identify the Nature of the Alleles**:
- \( I^A \) and \( I^B \) are co-dominant alleles. This means that when both alleles are present in an individual, they will both be expressed.

3. **Determine the Possible Blood Groups**:
- The possible blood groups based on the combinations of these alleles are:
- **A Blood Group**: Genotypes can be \( I^A I^A \) or \( I^A i \).
- **B Blood Group**: Genotypes can be \( I^B I^B \) or \( I^B i \).
- **AB Blood Group**: Genotype is \( I^A I^B \) (both \( I^A \) and \( I^B \) are expressed).
- **O Blood Group**: Genotype is \( ii \) (only recessive alleles).

4. **Analyze the Given Condition**:
- The question states that both \( I^A \) and \( I^B \) are present together. According to the principles of co-dominance, both alleles will be expressed.

5. **Conclusion**:
- Therefore, if both \( I^A \) and \( I^B \) are present, the resulting blood group will be AB.
- The correct answer to the question is that both alleles express, leading to the AB blood group.

### Final Answer:
Both \( I^A \) and \( I^B \) express together, resulting in the AB blood group.

---