ABO blood grouping is controlled by gene I which has three alleles and show co-dominance. There are six genotypes: How many phenotypes in all are responsible

Options

A. Six
B. Three
C. Four
D. Five

Answer

To solve the question regarding the phenotypes of ABO blood grouping controlled by gene I with three alleles (IA, IB, and IO), we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Alleles**:
The ABO blood group is determined by three alleles: IA, IB, and IO.

2. **List the Possible Genotypes**:
The combinations of these alleles lead to the following genotypes:
- IAIA (homozygous A)
- IAIB (heterozygous AB)
- IAIO (heterozygous A)
- IBIB (homozygous B)
- IBIO (heterozygous B)
- IOIO (homozygous O)

3. **Determine the Corresponding Phenotypes**:
Now, we will identify the phenotypes associated with each genotype:
- IAIA → Phenotype A
- IAIB → Phenotype AB
- IAIO → Phenotype A
- IBIB → Phenotype B
- IBIO → Phenotype B
- IOIO → Phenotype O

4. **Count the Unique Phenotypes**:
From the list of phenotypes, we can see:
- A (from IAIA and IAIO)
- AB (from IAIB)
- B (from IBIB and IBIO)
- O (from IOIO)

Thus, the unique phenotypes are A, AB, B, and O.

5. **Conclusion**:
Therefore, there are a total of **4 unique phenotypes** resulting from the 6 genotypes.

### Final Answer:
The number of phenotypes in all responsible is **4**.

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