reverse transcriptases 

https://doi.org/10.1351/goldbook.R05378
Enzymes found in retroviruses that can synthesize complementary single-strands of DNA from an mRNA sequence as template. They are used in genetic engineering to produce specific cDNA molecules from purified preparations of mRNA.
Source:
PAC, 1992, 64, 143. (Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)) on page 165 [Terms] [Paper]