Question

This pedigree shows the inheritance of colour blindness or sex-linked trait. Is this trait dominant or recessive? Is the mother of the colourblind girl in the F3 generation colourblind, a carrier or a person with normal colour vision? Explain. [4 MARKS]

Answer 1

Explanation:

1. The trait for color blindness is recessive.​
   
2. The mother of the colourblind girl in the F3 generation is a carrier because the girl in F3 generation can be colourblind only if her father is colourblind (which is also given in the Pedigree) and her mother has at least one abnormal gene (carrier).
   
3. But she is a carrier because 25% of her sons and daughters have normal colour vision as shown in the Pedigree.