Editing Reverse transcription polymerase chain reaction (section)

=== Gene insertion ===

RT-PCR can also be very useful in the insertion of [[eukaryotic]] genes into [[prokaryotes]]. Because most eukaryotic genes contain [[introns]], which are present in the genome but not in the mature mRNA, the cDNA generated from a RT-PCR reaction is the exact (without regard to the error-prone nature of reverse transcriptases) DNA sequence that would be directly translated into [[protein]] after [[transcription (biology)|transcription]]. When these genes are expressed in prokaryotic cells for the sake of protein production or purification, the RNA produced directly from transcription need not undergo splicing as the transcript contains only [[exons]]. (Prokaryotes, such as E. coli, lack the mRNA splicing mechanism of eukaryotes).