In retroviruses and retrotransposons, this cDNA can then integrate into the host genome, from which new RNA copies can be made via host-cell transcription.

Without reverse transcriptase, the viral genome would not be able to incorporate into the host cell, resulting in failure to replicate.

[citation needed] The process of reverse transcription, also called retrotranscription or retrotras, is extremely error-prone, and it is during this step that mutations may occur.

In order to accomplish this reposition, multiple steps and various enzymes including DNA polymerase, ribonuclease H(RNase H) and polynucleotide unwinding are needed.

[16] Initial reports of reverse transcriptase in prokaryotes came as far back as 1971 in France (Beljanski et al., 1971a, 1972) and a few years later in the USSR (Romashchenko 1977[17]).

These have since been broadly described as part of bacterial Retrons, distinct sequences that code for reverse transcriptase, and are used in the synthesis of msDNA.

[19] The reverse transcriptase employs a "right hand" structure similar to that found in other viral nucleic acid polymerases.

[20][21] In addition to the transcription function, retroviral reverse transcriptases have a domain belonging to the RNase H family, which is vital to their replication.

[22] Some fragments from the digestion also serve as the primer for the DNA polymerase (either the same enzyme or a host protein), responsible for making the other (plus) strand.

[25][26] It has been speculated that this template switching activity of reverse transcriptase, which can be demonstrated completely in vivo, may have been one of the causes for finding several thousand unannotated transcripts in the genomes of model organisms.

The first, the forced copy-choice model, proposes that reverse transcriptase changes the RNA template when it encounters a nick, implying that recombination is obligatory to maintaining virus genome integrity.

[30][28] As HIV uses reverse transcriptase to copy its genetic material and generate new viruses (part of a retrovirus proliferation circle), specific drugs have been designed to disrupt the process and thereby suppress its growth.

The commercial availability of reverse transcriptase greatly improved knowledge in the area of molecular biology, as, along with other enzymes, it allowed scientists to clone, sequence, and characterise RNA.