Question

If miR-277 reduces acyl-CoA dehydrogenase mRNA levels to 50% of control levels, which of the following results is most consistent with the expected qPCR result? (Note: Ct is the threshold cycle, the PCR cycle number at which mRNA levels have been amplified to a prespecified final level.)

A. miR-277 causes Ct to decrease to half the Ct value of control.
B. miR-277 causes Ct to increase by one cycle, relative to control.
C. miR-277 causes Ct to increase by two cycles, relative to control.
D. miR-277 causes Ct to decrease by an unpredictable amount.

Answer 1

miR-277 reducing mRNA levels to 50% would result in a uniform increase of one additional Ct cycle in qPCR, as each cycle in qPCR doubles the amount of DNA.

Step-by-step explanation:

If miR-277 reduces acyl-CoA dehydrogenase mRNA levels to 50% of control levels, the most consistent result with the expected qPCR result would be that miR-277 causes the Ct to increase by one cycle, relative to control.

In quantitative PCR (qPCR), the Ct (threshold cycle) is the cycle number at which the fluorescence of the amplified DNA reaches a threshold level. Decreasing the target mRNA levels by half would mean that it takes one additional PCR cycle to reach this threshold, as each cycle theoretically doubles the amount of DNA. Option B correctly represents this outcome, as every additional cycle in qPCR implies the initial quantity of target DNA is reduced by half.