Does the number of RNA reads per cell obtained from the 10X scRNA experiment depend on amount of mRNA in given cell?

Question

[Karol]

Hey! As we know, the amount of RNA reads per cell obtained from 10X scRNA experiment vary between cells. I wonder if this is effect of technical issues or does the number of RNA reads per cell obtained from the 10X scRNA experiment depend on the amount of mRNA in that cell? For the latter to be the case, we would have to read almost all the mRNA fragments in a cell, which I don't think is likely. Thank you for your replies in advance!

[rpolicastro]

There is an approximate upper limit to the number of unique cDNAs captured in any particular droplet because of variability and technical limitations of the library prep method itself. Beyond the library prep method there are a few other factors that can contribute, such as cell type (red blood cells having low RNA content as an example), cell viability, and single cell suspension quality.