IS there is equation for detection of n= of DNA copies in conventional PCR product by measuring pcr product against spectrophotometer
I agree with Artur's succinct and accurate answer. It would be easy to find the extinction coefficient for the dna amplimer and use it to measure the amount of dna once the amount was in the measuring range of the spectrophotometer but there is a problem with knowing the exact efficiency of each cycle of pcr. This efficiency will change as the pcr reaction moves out of the linear range at higher cycle numbers and if you do not know the efficiency then given a single end point for normal pcr extrapolating back to a number of dna molecules will be very inaccurate. If you sample the reaction at low cycle numbers then with small amounts of dna will be difficult to measure accurately in the uv range.
You use Beer's Law to determine DNA concentration, BUT copy number depends on the size of your PCR product. Why are you trying to determine copy number with a spec? Use a nanodrop or Qbit or estimate on an agarose gel next to a ladder.
1. Conventional PCR cannot be used to accurately evaluate copy number (Journal reviewers might not accept the results). You should at least use Quantitative PCR (qPCR), or real-time PCR to estimate copy numbers, if you are not aiming for Southern analysis.
2. Nowadays, more advaced and newer PCR technolog "droplet digital PCR (ddPCR)" is used to detect copy number with more accurate results by researchers.
See paper: "Using droplet digital PCR (ddPCR) to detect copy number variation in sugarcane, a high-level polyploid (2016)"
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