If a colourblind woman marries a normal visioned man, their sons will be:

If a colourblind woman marries a normal visioned man, their sons will be:
  1. all colourblind
  2. all normal visioned
  3. one-half colourblind and one-half normal
  4. three-fourth colourblind and one-fourth normal

Solution

Colour blindness is a hereditary disease in which the gene for this disease is located on the X-chromosome. So, if a colour-blind woman marries a normal man, then it will produce all colour blind $\left(\mathrm{X}^{\mathrm{C}} \mathrm{Y}\right)$ sons. In the case of a carrier woman, the probability of a colour-blind son and a normal son is 50:50.

Asked in: NEET 2006

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