Lesson: Chapter 20 — Heredity

20.6. Genetic disorders 6 of 8 Reset answers

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Question 6

Two thalassaemia carriers marry. What is the chance that any one of their children has thalassaemia?

A All of them B One in four C One in two D None

The right answer is the one marked above.

One in four. Both parents are Tt, so the four boxes are TT, Tt, Tt and tt. Only tt has the condition.

Neither parent is ill and neither shows any sign of it. That is what a recessive allele does, and it is why carrier testing matters in Sri Lanka.

Answer the question to continue.