MHT CET Medical202623 April 2026Morning ShiftBiologyPrinciples of Inheritance and VariationActual
A normal woman whose father was colourblind is married to a normal man, (assuming equal distribution of female gametes), then _________.
Options
- A50 % of their sons will be colourblind.
- BAll the sons will be colourblind.
- CAll the sons will be normal.
- D75 % of the sons will be colourblind.
Correct answer
A. 50 % of their sons will be colourblind.
Step-by-step solution
Colour blindness is an X-linked recessive trait. Let X^C be the normal allele and X^c be the allele for colour blindness. The woman's father was colourblind ( X^c Y ), so he passed the X^c chromosome to her. Since she is normal, her genotype is X^C X^c (carrier). The normal man has the genotype X^C Y . A cross between the carrier woman ( X^C X^c ) and the normal man ( X^C Y ) produces the following offspring: Daughters: X^C X^C (normal) and X^C X^c (normal carrier). Sons: X^C Y (normal) and X^c Y (colourblind). Sin