The failure of the genome - If inherited genes are not to blame for our most common illnesses..?

Guardian.co.uk ^ | 17 April 2011 | Jonathan Latham

[neverdem]

If inherited genes are not to blame for our most common illnesses, how can we find out what is?

Since the human genome was sequenced, over 10 years ago, hardly a week has gone by without some new genetic "breakthrough" being reported. Last week five new "genes for Alzheimer's disease" generated sometimes front-page coverage across the globe. But take a closer look and the reality is very different.

Among all the genetic findings for common illnesses, such as heart disease, cancer and mental illnesses, only a handful are of genuine significance for human health. Faulty genes rarely cause, or even mildly predispose us, to disease, and as a consequence the science of human genetics is in deep crisis.

The human genome sequencing project was based on a huge, but calculated, gamble. The then leaders-to-be of the project believed that faulty genes inherited from our parents were probably the cause of most disease. After all, many rarer diseases were already known to be genetic. So it seemed a small leap to suppose that inherited faulty genes would underlie common diseases, too.

There was, however, a problem with the basis for their confidence. The best scientific evidence in humans for genes as causes of common disease was based on comparing disease rates in genetically identical twins against rates in non-identical twins (who share 50% of their DNA). These comparisons, called heritability studies, aimed to measure the relative contributions of genetic variation versus environmental variation.

Although extremely widely used and cited, these studies were considered worthless by some geneticists. Richard Lewontin of Harvard University, for instance, called in 1974 "for an end to the measurement of useless quantities". Other critics pointed out that these experiments relied on the proposition that identical twins experienced no more identical environments than did non-identical twins, when it...

[momincombatboots]

Thanks for the Epigenetics Pingaroo! I often wonder if even things like violent tendencies are not related to Epigenetics. Maybe institutionalizing the children in screwls was a very bad idea.