NEET Solved Paper 2017 Question 75
Question: The genotypes of a Husband and Wife are $ {{|}^{A}}{{|}^{B}} $ and $ {{|}^{A}}|. $ Among the blood types of their children, how many different genotypes and phenotypes are possible?
Options:
A) 4 genotypes ; 4 phenotypes
B) 3 genotypes ; 3 phenotypes
C) 3 genotypes ; 4 phenotypes
D) 4 genotypes ; 3 phenotypes
Show Answer
Answer:
Correct Answer: D
Solution:
To determine the possible genotypes and phenotypes of the children given the genotypes of the parents, we need to consider the inheritance of blood types. The genotypes of the husband and wife are ( I^A I^B ) and ( I^A i ), respectively.
Let’s list the possible combinations of alleles the children can inherit from their parents:
-
From the father (( I^A I^B )):
- The child can inherit either ( I^A ) or ( I^B ).
-
From the mother (( I^A i )):
- The child can inherit either ( I^A ) or ( i ).
Now, we can combine these alleles to find the possible genotypes of the children:
- ( I^A ) from the father and ( I^A ) from the mother: ( I^A I^A )
- ( I^A ) from the father and ( i ) from the mother: ( I^A i )
- ( I^B ) from the father and ( I^A ) from the mother: ( I^A I^B )
- ( I^B ) from the father and ( i ) from the mother: ( I^B i )
So, the possible genotypes of the children are:
- ( I^A I^A )
- ( I^A i )
- ( I^A I^B )
- ( I^B i )
These are 4 different genotypes.
Next, let’s determine the phenotypes corresponding to these genotypes:
- ( I^A I^A ): Blood type A
- ( I^A i ): Blood type A
- ( I^A I^B ): Blood type AB
- ( I^B i ): Blood type B
So, the possible phenotypes of the children are:
- Blood type A
- Blood type AB
- Blood type B
These are 3 different phenotypes.
BETA
