O-LevelBiologyGenetics & Variation5090/12 · May/June 2014 · Q381 Mark

In the inheritance of blood groups in humans, the MN system is controlled by a single gene. The gene has two alleles, M and N, that are co-dominant. The offspring of two parents were two boys of blood group MN and M and a girl of blood group N. What are possible genotypes of the parents?

AMM, MN

BMN, MN

CNN, MM

DNN, MN

✓ Correct answer

B: MN, MN

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Topic: Genetics & Variation, O-Level Biology (syllabus 5090). Multiple choice, 1 mark.
Source: O-Level Biology, May/June 2014 Paper 1 Variant 2, question 38.

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