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JAMB Biology 1992 Question 45

Question 45

Chromosomes, DNA and Sex Linkage

Women do not suffer from colour blindness because

  1. A.the trait is sex-linked
  2. B.only men are colour blind
  3. C.the genes are recessive and sex-linked
  4. D.the genes occur on both the X and Y chromosomes.
Show the answer and explanation

Answer: C (the genes are recessive and sex-linked)

Explanation

The gene is recessive and on the X chromosome; a woman has two X chromosomes, so a normal allele on the other X usually masks it.