Researchers at the University of Iowa have identified
certain genetic profiles that may be linked to a person's risk for developing
nicotine addiction and other psychological behaviors. Using a genome-wide scan,
scientists analyzed blood samples from smokers versus nonsmokers and found
similar genetic patterns among smokers that may one day be used as a genetic
test to determine who may be more vulnerable to nicotine addiction.
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Smoking signs: Scientists at the University of Iowa have discovered a genetic profile in smokers that may determine a person's risk of developing nicotine addiction.
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"When you look at substance-abuse
disorders and antisocial behavior, these are the last vestiges of the belief
that mental impairments are related to moral will," says Tracy Gunter, director
of forensic psychiatry at the University
of Iowa and a coauthor of
the study. "And one of the exciting things in this work is [that] it's
beginning to form ideas that folks with these disorders are biologically
different."
In the past few
years, researchers around the world have zeroed in on various genetic regions
believed to be involved in one's vulnerability to addiction. Some have studied
genes that control certain neurotransmitters in the brain, while others have
looked at genes related to addictive traits like risk taking and impulsivity.
Gunter and her colleagues chose to look at the genome as a whole and observe
which genes are turned on and which turned off in people with a long history of
smoking.
"One gene itself
doesn't tell you whether you have a disorder," says Robert Philibert, a
University of Iowa professor of psychiatry and the study's lead author. "But if
you measure 30 or 40, you come up with a good risk. So what we do is spot the
biology."
In this latest study, published in the American Journal of Medical Genetics, Philibert and his colleagues analyzed the
DNA samples of 94 people, some smokers and some nonsmokers. Using a technique
called transcriptional profiling, they looked at all 30,000 genes of the human
genome, fluorescently labeling those that were turned on versus those that were
turned off in both groups. What they found was both promising and daunting: 579
genes were more activated and 584 other genes were less activated in smokers
versus nonsmokers.
"This is sort of
like shining a light in a tomb," says Philibert. "It says there's a lot here,
but it doesn't tell you anything about it. In order to really explore the
biology, people will have to replicate this."
Gunter adds that few psychological behaviors exist alone.
For example, people who smoke may also have panic disorders or depression, each
of which may involve a number of different genes. "How do you sort that out?" Gunter asks. "Is a genetic test disorder- specific, or specific to a cluster of
disorders? There may be some sites that contribute more to prediction of a
disorder than other sites. In the years to come, could we prune that down?
Maybe."
Tags
addiction biology flourescent genetics genome