If XN is the dominant allele for normal vision and Xn the recessive allele for colour blindness, a boy with the genotype YXn will be

  • A have normal vision
  • B be colour-blind
  • C be totally blind
  • D be a carrier of colour blindness

The correct answer is D. be a carrier of colour blindness

The boy is a carrier  because Xn the recessive allele for colour blindness

Previous question Next question