complementary DNA. A DNA version of RNA, usually referring to messenger RNA – so a DNA version of an edited gene (edited through splicing to remove the regulatory introns). Basically, it’s a DNA version of the copy of a protein recipe that is used by ribosomes to make proteins in the process of translation. cDNA is what you put in to plasmids to get cells to make a protein for you (you don’t want to give them a version with introns!). It’s also what you work with when doing RT-qPCR to measure mRNA levels and its what you typically sequence when you do “RNA seq.” This is because it’s a lot more stable than RNA and easier to manipulate in the lab (make copies through PCR, clone into plasmids to make cDNA libraries, etc.).
