passwella.
Menu

JAMB Biology 1987 Question 44

Question 44

Chromosomes, DNA and Sex Linkage

In which of the following crosses will all the female offspring be colour blind?

  1. A.colour blind mother x colour blind father
  2. B.Colour blind mother x normal father
  3. C.Carrier mother x colour blind father
  4. D.Carrier mother x normal father.
Show the answer and explanation

Answer: A (colour blind mother x colour blind father)

Explanation

Daughters get one X from each parent. Only when both parents' X chromosomes carry the colour-blind allele (XcXc × XcY) are all daughters colour blind.