NEW!

UNRAVELING THE SECRET OF LIFE: DNA self-duplication, the basic precept of biotechnology, is denied

by Barry Commoner
GeneWatch
May-June 2003

References

Unraveling the DNA Myth: The Spurious Foundation of Genetic Engineering

by Barry Commoner
Harper's Magazine
February 2002

Synopsis
References

The Central Dogma

One of the most remarkable features of molecular genetics is the speed with which its technical terms - DNA and genes - have become embedded in popular culture. This is a tribute to the appealing simplicity of the awesome idea behind these words - that something as lifeless as a molecule creates all of the numerous and wonderfully diverse natural endowments of living things. How that profound process is believed to happen - the science's governing precept - is generally known as "the central dogma."

The central dogma was originally described by Francis Crick in his germinal 1958 paper, and this seemed a seemed a reasonable way, in the Harper's article, to frame a critical analysis of molecular genetics. Crick's theory consists of two precepts, one he called the "Sequence Hypothesis" and the other the "Central Dogma." Very quickly, molecular geneticists - reflecting, perhaps, their intense belief in what they were doing - adopted the central dogma as the term for the overall theory on how inheritance is governed by DNA genes. But ironically, while its name has survived, the Central Dogma itself has not. Now that name applies only to a more complex version of Crick's Sequence Hypothesis, which has alone been widely accepted as the guiding precept of molecular genetics.

With the substantive responses to the Harper's article in hand, it becomes clear that this semantic mutation has immunized the science against the conceptual impact of discordant data, a failing that accounts for most of its adherents' criticism of the article. This is best exemplified by two such responses that happen to come from reasonably authoritative sources. One is an editorial, "Wag the Dogma," commenting on the article, published in the April 2002 issue of Nature Genetics. The editorial's chief complaint is that the article wrongly argues that the massive Human Genome Project's most prominent result - that there are too few human genes to match the number predicted by the central dogma - represents the "downfall" of that theory. Rather, the editorial asserts:

"Crick's original proposal had nothing to do with the relationship between an organism's genome and its inherited traits; it simply stated that the information flow in the cell goes from nucleic acids to proteins."

However, the editorial's description of the central dogma is, in fact, a reasonably accurate rephrasing of only part of Crick's theory, The Sequence Hypothesis. According to Crick, this "assumes that the specificity of a piece of nucleic acid is expressed solely by the sequence of bases [or nucleotides] and that this sequence is a (simple) code for the amino acid sequence of a particular protein." It would appear that, contrary to Crick, the editors of Nature Genetics believe that the overall theory is contained in the Sequence Hypothesis alone, which has acquired the title of precisely that part of the original theory - the Central Dogma hypothesis - that has now been excluded from it.

This same linguistic distortion of Crick's theory appears as well in a letter to the editor from Dr. Steven L. Salzberg, a co-author of one of the two reports on the Human Genome Project (an abbreviated edited version of his letter was published in the May 2002 issue of Harper's):

"Barry Commoner's article is full of errors, misleading claims, and gross exaggerations.... First he claims that the 'central dogma' was 'tested between 1990 and 2001 in one of the largest and most highly publicized scientific undertakings of our time, the Human Genome Project.' I can assure your readers that the purpose of the human genome project was not to test the central dogma, which simply states that genetic information flows from DNA to RNA to proteins...."

Here again, the definition of Crick's theory has been reduced to the Sequence Hypothesis alone, as it has in most of the critical responses to the Harper's article.

NEXT