CBSE 2025, Set 1

Question

Study the pedigree chart given below, showing the inheritance pattern of blood group in a family:

![Pedigree Chart](https://www.edvaya.com/images/cbse/biology/2025/blood-group-pedigree.webp)

(a) Give the possible genotypes of individual 1 and 2.

Edvaya · Accepted Answer

The correct answer is Subjective. **SOLUTION** By analyzing the pedigree: * Individual 1 has Blood Group B. * Individual 2 has Blood Group A. * They produce offspring with blood groups AB (individual 5), B (individual 6), and A (individuals 4 & 7). * Furthermore, Individual 4 (Blood Group A) marries individual 3 (Blood group B), and they have a child (individual 8) with Blood Group O ($ii$). This means Individual 4 must carry the recessive allele $i$. * For Individual 4 to be $I^A i$, the parent with Blood Group A (Individual 2) or parent with Blood group B (Individual 1) must carry the recessive $i$ allele. Since they have children of both A and B blood types, both parents must be heterozygous. Therefore: * **Genotype of Individual 1 (Blood Group B):** $I^B i$ * **Genotype of Individual 2 (Blood Group A):** $I^A i$

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Biology > Reproduction And Genetics > Principles Of Inheritance And Variation

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