Question

I do have to quantify the difference in basic levels of expression for a given gene in two types of tissues. There is no treatment, just basic levels.

Before I had a control sample that I taken as a 1, then a treated sample was calculated based on that control (its values were subtracted), therefore a fold change could be calculated between two types of tissue.

Now there's no fold change, just bare numbers, so I wonder how we suppose to quantify delta-deltaCT ? (what are these references?)

Answer 1

When quantifying the difference in gene expression levels between two tissues without a treatment, you can still use the delta-delta CT method. This method compares the difference in cycle threshold (CT) values between the two tissues for the gene of interest. The delta-delta CT method can be used to quantitatively compare gene expression differences between two types of tissues.

Step-by-step explanation:

When quantifying the difference in basic levels of gene expression in two types of tissues without a treatment, you can still use the ΔΔCT method. This method compares the difference in cycle threshold (CT) values between the two tissues for the gene of interest. The CT value indicates the number of PCR cycles required for the fluorescent signal to cross a certain threshold. By subtracting the CT values of the two tissues, you can determine the ΔCT. This ΔCT can then be used to calculate the expression difference using the formula 2^-(ΔCT). The ΔΔCT (delta-delta CT) method can be used to compare the expression difference between samples.