Question

If a colour blind woman marries a normal visioned man, their sons will be

• A. all colour blind
• B. ¾ colour blind and ¼ normal
• C. all normal visioned
• D. one half colour blind and one half normal

Answer 1

The correct option is A all colour blind

Colour blindness is caused due to the inheritance of mutant alleles present on the X chromosome which hinders normal colour vision in the affected person. Based on the information provided in the question, the woman is colour blind (genotype X${}^c$X${}^c$) and the man has normal vision (genotype- XY). The following Punnett square can be used to represent the cross between the two parents.


According to the result obtained in the Punnett square, all the sons are colourblind.