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David Baltimore Ph.D.

David Baltimore Ph.D.

The Nobel Prize in Physiology or Medicine 1975

Co-Nobelists Renato Dulbecco, Howard M. Temin

Award: “for their discoveries concerning the interaction between tumour viruses and the genetic material of the cell.”

Thought Process
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Thought Process

Excerpt from autobiographical book by Harold Varmus, Medicine Nobelist, 1989, The Art and Politics of Science.

‘David Baltimore and Howard Temin and one of his postdoctoral fellows, Satoshi Mizutani, announced, first at important meetings and soon thereafter in adjacent papers in Nature magazine, that they had found—not in cells, but in the virus itself!—an enzyme that could copy the RNA genome of an RNA tumor virus into DNA.

The discovery of reverse transcriptase was stunning, among the most dramatic events in the history of modern biology. Why was the discovery of reverse transcriptase so dramatic? First, it clarified the meaning of the Central Dogma of molecular biology. The conventional flow of information transfer “from DNA to RNA to protein” was the essence of the Central Dogma, so to some the discovery that information could flow from RNA to DNA appeared to violate the rules. With the discovery of reverse transcriptase, the “reversed” flow of genetic information, from RNA to DNA, was now clearly possible and seemed likely to happen when RNA tumor viruses infected cells. The notion that information flowed “backward,” in the unaccustomed direction, from RNA to DNA, also inspired the new and now universally used name for RNA tumor viruses: retroviruses.’

Simple explanation

DNA gives rise to RNA which gives rise to Protein.
There are RNA viruses which infect cells and replicate within those cells.
Scientists used to think that cells infected by RNA viruses contain the chemical needed to convert RNA to DNA, enabling the virus to replicate.
Independently Temin and Baltimore discovered the chemical which they named ‘reverse transcriptase’ in the RNA of the virus. Reverse transcriptase converts RNA to DNA.
Scientists used to think that a particular chemical is in the infected cell. However, Temin and Baltimore discovered that the RNA virus carries within itself that which it needs to replicate. Scientists also thought that information flowed only in one direction from DNA to RNA. This discovery showed that information also flows in the opposite direction.

Learning point

Between A and B, one may think that something one is looking for is in A but it be may be in B. Also, sometimes one discovers that the opposite of current thinking exists.