Question

Match List-I with List-II:

Choose the correct answer from the options given below:

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (I), (B) - (III), (C) - (II), (D) - (IV)
• (A) - (I), (B) - (II), (C) - (IV), (D) - (III)
• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Hint:

ABO Cross Quick Rules:
- $AO \times BO$ yields all four blood groups ($A, B, AB, O$).
- Pure homozygous parent crosses ($AA \times AA$ or $BB \times OO$) result in only 1 phenotype ($A$ or $B$).

Answer 1

The Correct Option is D

Concept:
The human ABO blood group is governed by the multiple allelic locus $I$, with three alleles: $A$, $B$, and $O$.
Alleles $A$ and $B$ are co-dominant, and both are completely dominant over the recessive allele $O$.
This question requires determining the possible phenotypic outcomes for offspring from given parental mating crosses.

Step 1: Analyzing Parental Crosses (A) and (B):
1. Cross (A): $AA \times AA$:
Both parents produce only $A$ gametes. All offspring have genotype $AA$, yielding exclusively phenotype A. Thus, (A) matches (III).
2. Cross (B): $AO \times AO$:
Gamete combinations produce genotypes $1\,AA : 2\,AO : 1\,OO$.
Genotypes $AA$ and $AO$ express phenotype A, while $OO$ expresses phenotype O. Thus, the phenotypes are A and O. Thus, (B) matches (IV).

Step 2: Analyzing Parental Crosses (C) and (D):
1. Cross (C): $BB \times OO$:
Parent 1 contributes only allele $B$ and Parent 2 contributes only allele $O$. All offspring will have genotype $BO$, producing exclusively phenotype B. Thus, (C) matches (I).
2. Cross (D): $AO \times BO$:
Combining gametes yields genotypes $AB$ (phenotype AB), $AO$ (phenotype A), $BO$ (phenotype B), and $OO$ (phenotype O). All four phenotypes (A, B, AB, and O) are produced. Thus, (D) matches (II).

Step 3: Final Answer:
The matching is:
(A) $\rightarrow$ (III), (B) $\rightarrow$ (IV), (C) $\rightarrow$ (I), (D) $\rightarrow$ (II).
This matches Option (D).