Question

Color blindness in humans is controlled by a gene located on the X chromosome (sex-linked). The normal gene, Xc need only be present as a single copy for an individual yo have normal vision. Since males and femaleshave diffrent numberss of X chromosomes , the incidence of color blindnes between sexes.

If a color blind man marries a women with normal vision whoses father was color blind, what proportion of there sons and daughters would you expect to be color blind ? Use Xc for the normal gene, Xc for the mutant gene and Y for male chromosomes.

Answer 1

As male is colur blind he will always produce mutant X_C gene containing X cromosome for colour blind whereas women will produce one normal X_c gene containing X chromosome and one mutatant X_C gene containing X-cromosome (which she has inheritated from her father).

Therefore, upon mating there are 50% chances of colour blind son and 50% chances of son with normal vision.

whereas there are 50% chances of colour blind daugher and 50% chances of normal vision daugher who will be the carrier for colour blind disorder.