Question

A woman has normal vision but her father was colour blind. If she is married to a colour blind person, report on the occurrence of the disease in the progeny.

Answer 1

A woman has normal vision but her father was colour-blind. This means she is a carrier of the disease and has the genotype X_NX_n. The genotype of a colour-blind man is X_nY. The chances of occurrence of the disease in progeny are as follows.

Gametes	Xn	Y
XN	XNXn Carrier daughter	XNY Normal son
Xn	XnXn Colour-blind daughter	XnY Colour-blind son