In biochemistry, reverse transcriptase (EC 126.96.36.199), also known as RNA-directed DNA polymerase, is an enzyme that is able to transcribe RNA into DNA. That is, reverse transcriptase is able to copy genetic information from RNA to DNA, which is the reverse of the more typical direction (DNA to RNA ? see central dogma of molecular biology).
Every retrovirus has a reverse transcriptase enzyme, which enables it to transcribe the genetic information from its RNA into DNA, which can then be integrated into the host genome. Similarly, retrotransposons copy themselves to RNA and then, via reverse transcriptase, back to DNA.
Reverse transcriptases also occur in group II introns, bacterial msDNAs, hepadnaviruses, and caulimoviruses.
Reverse transcriptase has a high error rate (up to about 1 in 2,000 bases) when transcribing RNA into DNA. This high error rate allows retroviruses to mutate rapidly.
DNA (deoxyribonucleic acid) stores an organism's genetic code. RNA (ribonucleic acid) is used to take sequences in the DNA and synthesize corresponding proteins by carrying the sequences to a ribosome. It does this by almost magically uncurling the DNA spiral (with the help of some proteins) and lining itself up with the exposed base pairs to make an inverted copy, or a transcription. RNA uses the same four base pairs as DNA, with the exception of using uracil instead of thymine.