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Q5 - Detecting Aneuploidy by PCR Fragment Analysis

Theoretical 2 Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license
Chromosomal Variation: Number & Structure

Electrophoresis patterns of PCR products of several chromosome pairs (pairs shown on bottom) in five different individual (1-5) in figure below allow evaluation of presence or absence of chromosome number abnormality. Monosomy of autosomal chromosomes is known to be lethal. Relative height of the peaks in each box reflects the copy number ratio of the two chromosomes in that box. The horizontal axis shows migration, and the vertical axis shows fluorescence intensity.

Figure 1. Figure 1.

Using the information and data, determine which of the statements are true or which are false.

A. Three individuals show trisomy.
B. Two individuals show abnormal monosomy.
C. Two individuals have normal karyotypes.
D. PCR products related to different chromosomes should have different sizes to allow copy number evaluation.
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Question reproduced from IBO 2018, Theoretical Paper 2, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)