Howard Temin

Howard Temin was an American virologist and geneticist at the University of Wisconsin-Madison who, studying RNA tumor viruses, proposed years before it could be experimentally confirmed that such viruses must carry the enzymatic ability to copy their genetic information from RNA back into DNA inside an infected cell, a reversal of the normally assumed one-way flow of genetic information from DNA to RNA. This idea was met with considerable skepticism from much of the scientific community when Temin first proposed it in the 1960s, but in 1970 he isolated and demonstrated the enzyme responsible, reverse transcriptase, at almost exactly the same time that David Baltimore independently reported the same discovery working with a different virus. The finding proved fundamental to modern molecular biology and medicine, since reverse transcriptase is now known to be essential to the life cycle of retroviruses including HIV, the virus that causes AIDS, and the enzyme itself became an indispensable everyday tool in genetic engineering and diagnostic laboratories worldwide. Temin shared the 1975 Nobel Prize in Physiology or Medicine with Baltimore and Renato Dulbecco for their discoveries concerning the interaction between tumor viruses and the genetic material of the cell, and he remained on the faculty at the University of Wisconsin-Madison for the whole of his research career.