Friday, September 12, 2008

On the central Dogma of Molecular Biology


Crick, F. (1970): Central Dogma of Molecular Biology. Nature 227, 561-563. PMID 4913914

The central dogma of molecular biology deals with the detailed residue-by-residue transfer of sequential information. it states that such information cannot be transferred from protein to either protein or nucleic acid.

The Central Dogma. This states that once “information” has passed into protein it cannot get out again. In more detail, the transfer of information from nucleic acid to nucleic acid, or from nucleic acid to protein may be possible, but transfer from protein to protein, or from protein to nucleic acid is impossible. Information means here the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein.

Crick, F.H.C. (1958) On protein

I just sat through two classes today where the lecturer made comments about the central dogma and was Wrong. The central dogma proposed by Francis crick is not the same as the positive statement put out by Watson in his book genetics.
Watson’s version of the Central Dogma. This figure is taken from the first edition of The Molecular Biology of the Gene (p. 298)

Here is a quote from Larry Moran (Professor in the Department of Biochemistry at the University of Toronto) who knows what the central dogma is actually about. (link)
So, how do we explain the current state of the Central Dogma? The Watson version is the one presented in almost every textbook, even though it is not the correct version according to Francis Crick. The Watson version has become the favorite whipping boy of any scientist who lays claim to a revolutionary discovery, even though a tiny bit of research would uncover the real meaning of the Central Dogma of Molecular Biology. The Watson version has been repeatedly refuted or shown to be incomplete, and yet it continues to be promoted as the true Central Dogma. This is very strange.

The Crick version is correct—it has never been seriously challenged—but few textbooks refer to it. One exception is Lewin’s GENES VIII (Lewin, 2004) (and earlier editions). Lewin defines the Central Dogma of Molecular Biology as,
The central dogma states that information in nucleic acid can be perpetuated or transferred but the transfer of information into protein is irreversible. (B. Lewin, 2004)
I recommend that all biochemistry and molecular biology teachers adopt this definition—or something very similar—and teach it in their classrooms.

Crick, F.H.C. (1958) On protein synthesis. Symp. Soc. Exp. Biol. XII:138-163
Crick, F. (1970) Central Dogma of Molecular Biology. Nature 227, 561-563. [PDF file]
Watson, J.D. (1965) The Molecular Biology of the Gene. W.A. Benjamin. Inc. New York

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