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No Easy Link Between Genes, Behavior |
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Written by Keay Davidson, Chronicle Science Writer
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DNA Studies Dash Quest for Easy Answers
Genome's link to behavior hard to prove (excerpt)
It has become a mantra for our age: Your DNA is your destiny.
Over the last few decades, numerous scientists claimed to have found genetic and neuro-anatomical "explanations" for human behaviors, including sexual orientation, mental illnesses, alcoholism and other human traits.
But in retrospect, those scientists may have seriously underestimated the complexity of links between genes and human behavior -- or human anything. . . .
In retrospect, claims of links between genes and complex human traits have two things in common: They almost always make headlines, but they're almost never easily verified -- "replicated," in scientific jargon -- by other researchers.
One of the most publicized scientific claims of the last decade -- that gays and straights have different brains -- illustrates the point.
In 1991, Salk Institute researcher Simon LeVay made international headlines when he reported finding a significant structural difference between the brains of gay and straight men.
Based on LeVay's analysis of 41 autopsied brains, he reported that a particular brain feature -- technically speaking, the third interstitial nucleus of the anterior hypothalamus -- tends to be larger in straight males than in gay males.
But now, despite studying twice as many brains as were analyzed by LeVay, a New York neuroanatomist has been unable to either verify or disprove the Salk scientist's claim.
"I wouldn't go as far as to say that my study was 'negative.' (Rather), it was inconclusive," says Dr. Bill Byne, a neuroanatomist and psychiatrist on the faculty at Mt. Sinai School of Medicine in New York, whose results are scheduled for publication later this year in the journal Hormones and Behavior.
The news drew a stoic reaction from LeVay, who is now a freelance science writer in Southern California.
"Obviously I would have liked a resounding confirmation" LeVay said by phone yesterday. "From what I've heard it doesn't sound like a resounding confirmation, and in that way I'm disappointed. But we'll just have to wait" for further research. . . .
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Copyright © 2000, All rights reserved, San Francisco Chronicle. Used by permission of the author. |
