Now What?: Apr 20, 2011

Since the human draft genome was published more than 10 years ago, researchers have found many genes linked to various diseases, says the Guardian's Jonathan Latham. In fact, he notes that last week, researchers discovered five new genes linked to Alzheimer's disease, bringing the number of genes associated with the illness to 10. But what have those researchers really found? Among all the genes found to influence risk for common diseases like heart disease, Alzheimer's, and cancer, only a few are significant to human health, Latham says. "Faulty genes rarely cause, or even mildly predispose us, to disease, and as a consequence the science of human genetics is in deep crisis," he adds. The leaders of the human genome sequencing project thought that the cause of most disease was likely to be genes inherited from our parents, just like many rare diseases were know to be genetic. But that assumption was based on heritability studies, and it is now thought that these studies are flawed and that the reason genes for common diseases haven't really been found is because they don't actually exist, Latham says. "The failure to find meaningful inherited genetic predispositions is likely to become the most profound crisis that science has faced," he adds. "The likelihood that further searching might rescue the day appears slim. A much better use of that money would be to ask: if inherited genes are not to blame for our commonest illnesses, can we find out what is?"