A man with blood group 'A' marries a woman with group 'B' blood.Their child has blood group 'O' what are the gentypes of the parents ?

Options

A. `I^(A)I^(A),I^(B)I^(B)`
B. `I^(A)`i`,I^(B)i`
C. `I^(A)`i`,I^(B)I^(B)`
D. `I^(A)I^(B),I^(A)I^(B)`

Answer

To determine the genotypes of the parents given that the man has blood group 'A', the woman has blood group 'B', and their child has blood group 'O', we can follow these steps:

### Step 1: Understand Blood Group Inheritance
Blood groups are determined by the presence of specific alleles. The alleles for blood groups are:
- A (IA)
- B (IB)
- O (i)

The possible genotypes for each blood group are:
- Blood group A: IAIA (homozygous) or IAi (heterozygous)
- Blood group B: IBIB (homozygous) or IBi (heterozygous)
- Blood group AB: IAIB
- Blood group O: ii

### Step 2: Analyze the Child's Blood Group
The child has blood group 'O', which means the genotype must be ii. For a child to have blood group O, each parent must contribute an 'i' allele.

### Step 3: Determine Possible Genotypes of the Parents
1. **Father's Genotype (Blood Group A)**:
- If the father has blood group A, his possible genotypes are IAIA or IAi.
- Since the child has blood group O (ii), the father must be heterozygous (IAi) to provide the 'i' allele.

2. **Mother's Genotype (Blood Group B)**:
- If the mother has blood group B, her possible genotypes are IBIB or IBi.
- Similarly, the mother must also be heterozygous (IBi) to provide the 'i' allele.

### Step 4: Conclusion
Both parents must be heterozygous for their respective blood groups in order to have a child with blood group O. Therefore, the genotypes of the parents are:
- Father: IAi (Blood group A)
- Mother: IBi (Blood group B)

### Final Answer
- Father's Genotype: IAi
- Mother's Genotype: IBi

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