3.    Colourblindness is a sex-linked recessive condition. This means that the characteristic is carried only on the X chromosome. Females therefore have two alleles for the trait, and males have only ONE.

(a)    Draw a key to show the genotypes and phenotypes for this trait (like the example in question 1)
(b)    If a colourblind female were to mate with a normal male, what would the chance be that they produced a colourblind daughter? (show all of your working, set out correctly to indicate Parents, Gametes and F1)