Blood grouping in human beings is controlled by

Options

A. 4 alleles in which A is dominant
B. 3 alleles in which A and B are codominant and `i` is recessvie
C. 3 alleles in which one is dominant
D. 3 alleles in which A is dominat

Answer

**Step-by-Step Solution:**

1. **Understanding Blood Groups:** Blood grouping in humans is determined by specific alleles. The primary blood groups are A, B, AB, and O.

2. **Identifying the Alleles:** There are three main alleles involved in human blood grouping:
- **I^A (A allele)**
- **I^B (B allele)**
- **i (O allele)**

3. **Dominance and Co-dominance:**
- The A allele (I^A) and B allele (I^B) are both dominant over the O allele (i).
- When both A and B alleles are present (genotype I^A I^B), they exhibit co-dominance, meaning both alleles are expressed simultaneously, resulting in the AB blood group.

4. **Recessive Allele:** The O allele (i) is recessive, meaning that it will only express the O blood type when present in a homozygous state (ii).

5. **Conclusion:** Therefore, blood grouping in human beings is controlled by three alleles: A (I^A), B (I^B), and O (i), where A and B are co-dominant and O is recessive.

**Final Answer:** Blood grouping in human beings is controlled by three alleles: A (I^A), B (I^B), and O (i), where A and B are co-dominant and O is recessive.

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