Q. A colour blind daughter is born-to
Solution:
Colourblindnessisarecessivesex-linked trait in which the eye fails to distinguish red and green colours. The gene for the normal vision is dominant, The normal gene and its recessive allele are carried by Xvchromosomes. In females; colour blindness. appears only when both the sex chromosomes carry the recessive gene. The females have normal vision but function as carrier if a single recessive gene for colour blindness is present (XXc). However, in human males the defect appears in the presence.of a single recessive gene (XcY) because Y-chromosome ofrnale does not carry any gene. for colour vision. Colour blindness, like any other sex-linked · trait, shows criss-cross inheritance. A cross between a. carrier mother and colour blind father can be represented as follows: In other combinations we will get carrier girl only, not any colour blind girl.
