If a father and son are both defective in red-green colour vision, is it likely that the son inherited the trait from his father? Comment.

Gene for colourblindness is X-chromosome linked, and sons receive their sole from their mother, not from their father. Male-to-male inheritances is not possible for X-linked traits in humans. In the given case the mother of the child must be a carrier. (heterozygous) for colour blindness gene.