Question:hard
Which of the following tests is not used for detection of specific aneuploidy?
Which of the following tests is not used for detection of specific aneuploidy?
Show Hint
One option measures mRNA expression, not chromosome copy number.
Updated On: Jun 24, 2026
- FISH
- RT-PCR
- QF-PCR
- Microarray
Show Solution
The Correct Option is B
Solution and Explanation
To answer this we must separate tools that count chromosomes from tools that read gene activity. Aneuploidy is a problem of chromosome number, so the odd one out will be whatever cannot measure chromosome dosage.
Start with the genuine aneuploidy detectors. FISH lights up specific chromosomes with colored probes, and you literally count the spots: three signals for chromosome 21 means trisomy 21. QF-PCR is a rapid prenatal favorite that amplifies repeat markers and compares fluorescent peak heights, where an unusual ratio betrays an extra chromosome. Chromosomal microarray scans copy number genome-wide and will flag the gain of an entire chromosome just as easily as a small deletion, so it too detects aneuploidy.
That leaves RT-PCR. Its job is to turn messenger RNA into cDNA and quantify transcripts, which tells you how strongly a gene is being expressed, not how many copies of a chromosome a cell carries. It simply is not a chromosome-counting assay. Note the original answer key listed microarray, but that is wrong because microarray does catch whole-chromosome imbalances, so the corrected choice is RT-PCR.
\[\boxed{\text{RT-PCR}}\]
Start with the genuine aneuploidy detectors. FISH lights up specific chromosomes with colored probes, and you literally count the spots: three signals for chromosome 21 means trisomy 21. QF-PCR is a rapid prenatal favorite that amplifies repeat markers and compares fluorescent peak heights, where an unusual ratio betrays an extra chromosome. Chromosomal microarray scans copy number genome-wide and will flag the gain of an entire chromosome just as easily as a small deletion, so it too detects aneuploidy.
That leaves RT-PCR. Its job is to turn messenger RNA into cDNA and quantify transcripts, which tells you how strongly a gene is being expressed, not how many copies of a chromosome a cell carries. It simply is not a chromosome-counting assay. Note the original answer key listed microarray, but that is wrong because microarray does catch whole-chromosome imbalances, so the corrected choice is RT-PCR.
\[\boxed{\text{RT-PCR}}\]
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