one third of maximum florescence intensity

[genefuse]

Good day all,
My question pertains to calculating one third of maximum florescence intensity (MFI)
If the MFI is at 15 cycles then one third is 5 cycles.
Why the need to read of the amplification plot in the linear scale.

[SylvainL]

I am not sure I understand your point but I am curious

Is it at the library prep step, using PCR? If yes, your material will (almost) double at each cycle, so your asumption is wrong. If it is something else, I would be glad to learn something new today

[genefuse]

ATAC-seq

Hi SylvainL,
Thanks for your comment I will fill you in…

It is not my assumption it is a quote from Curr. Protoc. Mol. Biol. it pertains to ATAC-seq.

ATAC-seq: A Method for Assaying Chromatin AccessibilityGenome-Wide. Curr. Protoc. Mol. Biol. 109:21.29.1-21.29.9.

“17. To calculate the additional number of cycles needed, plot linear Rn versus cycle and determine the cycle number that corresponds to one-third of the maximum fluorescent intensity (see Fig. 21.29.2A).”

I was wondering if anyone has performed this calculation comparing linear to logarithmic amplification plots, and whether a formula exist to precisely determine “one-third of the maximum fluorescent intensity” without visually guessing from the amplification plot.

Cheers,