Biology Inheritance / Variation & Genetics MDCAT 2015
PMDC Verified Question 92 of 94
ABO blood system is an example of:
A
Polygenes
B
Multiple alleles
C
Multiple genes
D
Multiple mutation
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Multiple alleles
Concept:

While an individual diploid organism can only carry two alleles for a given gene, a population can possess many more variations of that gene.

Solution:

  • The ABO blood group system is the first discovered and most classic example of a multiple allelic system in humans.
  • It is controlled by a single gene locus (Gene I) on chromosome 9, which exists in three distinct allelic forms in the human population: \(I^A\), \(I^B\), and \(i\).


Why other options are incorrect:

  • Polygenes (Multiple genes): Refers to traits controlled by two or more separate genes (e.g., skin color or height), not multiple alleles at a single gene locus.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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