Friday, August 26, 2011

Revisiting the Central Dogma in the 21st Century

James A. Shapiro is an interesting character. He claims that he is opposed to both neo-Dawinism and Creationism (upper case "C") and he claims to offer a "Third Way." That "third way" appears to be indistinguishable from Intelligent Design Creationism although Shapiro never admits to being an advocate of intelligent design. Instead, he prefers to let his "science" do the talking and points out that it's science that leads us to the conclusion that life is designed.

Shapiro has published scientific articles with Richard Sternberg who advocates a similar position but who has become one of the poster boys of the Discovery Institute and one of the stars of the movie Expelled: No Intelligence Allowed. Like Sternberg, Shapiro is admired by IDiots [Non-supernatural ID?: University of Chicago microbiologist James Shapiro works with ID guys, dismisses Darwinism, offers third way].

One of the characteristics Shapiro shares with the IDiots is attacking evolution. In this post I want to review a paper he published in 2009 on "Revisiting the Central Dogma in the 21st Century" (Shapiro, 2009).

The correct version of the Central Dogma of Molecular Biology is:
... once (sequential) information has passed into protein it cannot get out again (F.H.C. Crick, 1958)

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. (F.H.C. Crick, 1970)
In other words, the flow of information is from nucleic acid to protein and never from protein to nucleic acid.

The incorrect version of the Central Dogma of Molecular Biology is what Crick referred to as the "Sequence Hypothesis" and what we now know as a simplified version of the standard pathway for information flow from genes that specify a protein product. The incorrect version is often presented in textbooks as the real Central Dogma although that's slowly changing [The Central Dogma Strawman].

None of this should be a problem for someone who is writing a scholarly article for the scientific literature since we expect such a person to have read the relevant references (Crick, 1958; Crick, 1970). They should get it right. Let's see how Shapiro does when he says ...
The concept was that information basically flows from DNA to RNA to protein, which determines the cellular and organismal phenotype. While it was considered a theoretical possibility that RNA could transfer information to DNA, information transfer from proteins to DNA, RNA, of other proteins was considered outside the dogma and "would shake the whole intellectual basis of molecular biology [Crick, 1970].
That sounds pretty good but the first part is a little troubling. Which version does Shapiro actually believe he's "revisiting"?

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