In the fields of molecular biology

Molecular biology

Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

 and biochemistry

Biochemistry

Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...

, a reverse transcriptase, also known as RNA-dependent DNA polymerase, is a DNA polymerase

DNA polymerase

A DNA polymerase is an enzyme that helps catalyze in the polymerization of deoxyribonucleotides into a DNA strand. DNA polymerases are best known for their feedback role in DNA replication, in which the polymerase "reads" an intact DNA strand as a template and uses it to synthesize the new strand....

 enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that transcribes

Transcription (genetics)

Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...

 single-stranded RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 into single-stranded DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

. It also helps in the formation of a double helix DNA once the RNA has been reverse transcribed into a single strand cDNA. Normal transcription involves the synthesis of RNA from DNA; hence, reverse transcription is the reverse of this.

Well studied reverse transcriptases include:

• HIV-1 reverse transcriptase from human immunodeficiency virus
  HIV
  Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
  
   type 1
• M-MLV reverse transcriptase from the Moloney murine leukemia virus
  Murine leukemia virus
  The murine leukemia viruses are retroviruses named for their ability to cause cancer in murine hosts. Some MLVs may infect other vertebrates. MLVs include both exogenous and endogenous viruses...
  
  
• AMV reverse transcriptase from the avian myeloblastosis virus
  Alpharetrovirus
  Alpharetrovirus is a genus of the retroviridae family. It has type C morphology. Members can cause sarcomas, other tumors, and anaemia of wild and domestic birds and also affect rats....
  
  
• Telomerase reverse transcriptase
  Telomerase
  Telomerase is an enzyme that adds DNA sequence repeats to the 3' end of DNA strands in the telomere regions, which are found at the ends of eukaryotic chromosomes. This region of repeated nucleotide called telomeres contains non-coding DNA material and prevents constant loss of important DNA from...
  
   that maintains the telomere
  Telomere
  A telomere is a region of repetitive DNA sequences at the end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Its name is derived from the Greek nouns telos "end" and merοs "part"...
  
  s of eukaryotic chromosomes

Reverse transcriptase was discovered by Howard Temin at the University of Wisconsin–Madison

University of Wisconsin–Madison

The University of Wisconsin–Madison is a public research university located in Madison, Wisconsin, United States. Founded in 1848, UW–Madison is the flagship campus of the University of Wisconsin System. It became a land-grant institution in 1866...

, and independently by David Baltimore

David Baltimore

David Baltimore is an American biologist, university administrator, and Nobel laureate in Physiology or Medicine. He served as president of the California Institute of Technology from 1997 to 2006, and is currently the Robert A. Millikan Professor of Biology at Caltech...

 in 1970 at MIT.