Hi, Asmaa.

To present a semi-quantitation result of either traditional PCR or qPCR data, we must know both exact number of copies of mtDNA molecules per mitochondrion and number of mitochondira per a specific tissue of the species of your interest. In particular, the sample of a tissue or cells should be one type that is not an easy task to achieve since if you take a plant tissue or animal tissue, there would be some mixing in the isolated tissues. Then, the mixed tissues may have over 2 different cell types unless an extreme care is taken. Different cell types will have different number of mitochondria per each cell type.

In PCR of gDNA, we know all mixed tissues may have similar number of cell types. However, you will always have only 2 copies of the target fragment in all different cell types, thus semi-quantitation is a relatively reliable means and justified. Sorry for that.

Best wishes.

Hey Asmaa,

Do you mean that to use mtDNA to determinate a specy by using species spesific PCR?

Unfortunately not, in the kingdom plantae, mtDNA is not that polymorphic in close species. In addition, many plants contains 2 different types of mtGenome that can be visulized easy via half-green plants. So these kind of PCRs may give results that can not be analized that easy.

But I still didnt understand what you mean with W/W ratio.

If would like to classify different species, please write me private message, I can share my ISSR and RAPD PCR protocols to distrinctspecies.