Friday, October 01, 2010

Genetics: DNA Causation Unravels

In several earlier posts here, I quoted from scientific journals reporting on the findings of modern genetic research -- or rather, the surprising absence of such findings.  For the first time ever, science has the tools to find out exactly where the genes are that we have long believed underly major diseases.  What the tools are telling us is that the supposed genetic causality isn't there, or it's much weaker than previously thought.  We can now say with confidence that the "alcoholism gene" does not exist; that the genetic contribution to alcoholism, such as it is, is spread over an as yet unknown number of genes, each of which has only a minute influence, and that this influence is profoundly mixed up with and moderated by environmental factors.
Now the current issue of Scientific American (Oct. 2010) reports similar findings for genetic research into a broad range of other diseases.  In its article, "Revolution Postponed: the Human Genome Project has failed so far to produce the medical miracles that scientists promised,"  the journal describes a growing realization in the scientific community that the old model of genetic science, where variations in specific genes cause specific illnesses, has very limited validity.    The journal quotes David Goldstein, director of the Center for Human Genome Variation at Duke University, one of the major research centers:
It's an astounding thing that we have cracked open the human genome and can look at the entire complement of common genetic variants, and what do we find? Almost nothing.  That is absolutely beyond belief.

Another researcher, David Botstein of Princeton, describes the effort to map disease-causing genetic variations as an experiment that had to be done in order to know that it did not work.  It was, he said, "a magnificent failure."

Walter Bodmer, a pioneer of the modern genomics research effort, says that the effort to find genetic variants that cause major diseases is a biological dead end.  "The vast majority of [common] variants have shed no light on the biology of diseases."

These findings are profoundly upsetting long-held beliefs about genetic causality and forcing scientists to rethink the whole model of what genes do.  The old model which saw DNA as a kind of computer program that determines the fate of the organism is out the window.  The processes are much more complex and involve a great deal more interaction with the environment than had been previously thought.

The takeaway for people who have serious issues with alcohol and/or other addictive substances is:  don't blame your genes.  Your genes are OK.  Your DNA will be just as happy, and very likely much happier, when you stop hammering your brain cells with addictive substances.

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