In the context of genetic disorders, consider the following : A woman suffers from colour blindness while her husband does not suffer from it. They have a son and a daughter. In this context, which one of the following statements is most probable) correct

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Q: 24 (IAS/2009)
In the context of genetic disorders, consider the following : A woman suffers from colour blindness while her husband does not suffer from it. They have a son and a daughter. In this context, which one of the following statements is most probable) correct ?

question_subject: 

Science

question_exam: 

IAS

stats: 

0,27,51,13,22,16,27

keywords: 

{'colour blindness': [2, 0, 1, 0], 'genetic disorders': [0, 0, 1, 0], 'husband': [0, 3, 2, 1], 'daughter': [1, 2, 4, 5], 'children': [0, 0, 1, 0]}

The probability of children inheriting color blindness depends on the genetics of the parents. Color blindness is a sex-linked recessive trait, linked to the X chromosome. A female has two X chromosomes (XX) and a male has one X and one Y chromosome (XY).

Option 1: Both children suffer from colour blindness: This is unlikely because the father, who does not have the trait, would pass his normal X chromosome to the daughter.

Option 2: Daughter suffers from colour blindness while son does not suffer from it. This is not possible because the daughter would receive a normal X chromosome from her father, and should not express color blindness.

Option 3: Both children do not suffer from colour blindness. This is not very probable; while the daughter is likely not to inherit color blindness, the son would inherit the X chromosome from the mother (that carries the trait) and become color blind.

Option 4: Son suffers from colour blindness while daughter does not suffer from it. This is the most probable scenario. The son would inherit the X chromosome carrying the defective gene from his mother and become color blind. The daughter, receiving a normal X chromosome from her father, would not.