The End of "Gene for _____"

 

Very nice story in the NYTimes today by Benedict Carey about the vexing complexity of gene-environment interaction. The story opens with this powerful news:

"One of the most celebrated findings in modern psychiatry — that a single gene helps determine one’s risk of depression in response to a divorce, a lost job or another serious reversal — has not held up to scientific scrutiny, researchers reported Tuesday." 

The original 2003 study had revealed what many were calling a "gene for depression." People with a particular variant of a gene involved in the regulation of neurochemicals seemed much more susceptible to depression when thrust into certain depressing life situations. 

But it's not that simple. In the vast majority of cases, genes don't dictate a trait or a specific response. They interact constantly with other genes and every other facet of a person's ongoing life. In school, we were taught that genes contain instructions on what each of us will be like. That was view 100 years ago. Now we understand that life is the consequence of constant gene-environment interaction. 

More from the Times story:

"The authors reanalyzed the data and found 'no evidence of an association between the serotonin gene and the risk of depression,' no matter what people’s life experience was, Dr. Merikangas said.

"By contrast, she said, a major stressful event, like divorce, in itself raised the risk of depression by 40 percent."

As a general rule, don't listen to anyone telling you that there's a "gene for" this or that. Even if there's an Ph.D. or M.D. at the end of the name, it's an old and misleading way of discussing genetics. 

Thankfully, it's not just the science that's improving. Reporting on genetics has also been getting demonstrably better. Today's piece is a nice example, as is this extraordinary piece by Carl Zimmer from last November. 

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Added June 30: A new piece by John Grohol, "Chasing the Genetic Ghosts of Mental Illness," speaks to this same critique.