Gce Model Questions Vol1 2018 Biology Question 10

Practice essay / theory question 10 from the 2018 Gce Model Questions Vol1 Biology examination. This question covers probability in genetics .

Gce Model Questions Vol1 2018 Biology Essay / Theory

Topic: probability in genetics

Question 10 GCE_MODEL_QUESTIONS_VOL1 • 2018 • BIOLOGY • essay

Gce Model Questions Vol1 2018 Biology Question 10 diagram

The diagram shows a three‑generation pedigree for a rare autosomal recessive disorder (shaded symbols). Squares represent males and circles represent females. The disorder is caused by the homozygous recessive genotype aa. The proband is the shaded male in generation III indicated by an arrow. Assume that the partner of the proband is unrelated, phenotypically normal and not a known carrier.

Question Parts

( a )

State the most likely genotype of each individual shown in the pedigree (I‑1, I‑2, II‑1, II‑2, II‑3, III‑1, III‑2, III‑3).

( b )

Using the genotypes deduced in part (a), calculate the probability that a future child of the proband (aa) with an unrelated, phenotypically normal partner will be affected by the disorder.

( c )

Explain, with reference to the pedigree, why the disorder is concluded to be autosomal recessive rather than X‑linked.

Detailed Solution & Marking Scheme

Get the step-by-step solution, key points required by examiners and detailed marking guidance through the Edcrib AI Tutor.

Reveal Answer

About This Question

This is Gce Model Questions Vol1 2018 Biology Question 10. It is one of the essay questions from the 2018 Gce Model Questions Vol1 Biology examination.

The question covers probability in genetics .

View More Gce Model Questions Vol1 2018 Biology Questions More Gce Model Questions Vol1 Practice Questions Back to Questions

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows

Chat with Support