Genes' impact can be altered

[Guest guest]

NATURE & NURTURE

Genes' impact can be altered

Genetic information can lead to helpful interventions for those needing

assistance to mitigate problems

http://www.newsday.com/news/health/ny-vpmar223767920apr22,0,6263758.story?co

ll=ny-health-headlines

 

BY GARY MARCUS

Gary Marcus, a professor of psychology at New York University, is the author

of " The Birth of the Mind: How a Tiny Number of Genes Creates the Complexity

of Human Thought. " This is from the Los Angele

 

April 22, 2004

 

 

The human brain has been described as everything from the " last frontier "

and " biology's greatest challenge " to " the most elaborate structure in the

known universe " and Woody Allen's " second-favorite organ. "

 

With rapid advances in genetics, neuroscience and psychology, we will soon

have a radically improved understanding of the contribution of genes to the

developing brain.

 

 

Used wisely, that knowledge could lead to an entirely new approach to

social intervention. But doing so will require overcoming common

misconceptions about how genes operate.

 

Genes are widely seen as either blueprints or deterministic dictators.

Neither view is correct. A single organism's collection of genes - its

genome - can lead to many different outcomes, depending on the surrounding

environment.

 

The African butterfly bicyclus anyana, for example, can take on two

different forms - colorful in the rainy season and dull brown in the dry

season - depending on how its genes are switched on and off.

 

The consequences of the responsiveness of genes to the environment may be

even more profound in a human. A butterfly's coloration pattern may only be

skin deep, but the switching of human genes in response to the environment

may profoundly shape our personalities.

 

Contrary to our usual belief that genes force us toward one possibility

rather than another, biology is revealing a different picture in which genes

arm us with ways of responding to different environments.

 

One example: A recent study - still preliminary, but breathtaking in what it

might mean - suggests that people who bear a particular version of an enzyme

known as MAO-A are predisposed to violence, but only if raised in abusive

environments.

 

This particular version of MAO-A is better thought of not as a gene " for

violence " but as a gene that leads its bearers to different kinds of

strategies, depending on their environments.

 

Given that genes themselves are responsive to the environment, and

responsive in different ways in different people, a bold new possibility

suggests itself, akin to an idea that has taken hold in medicine under the

name of pharmacogenetics.

 

The idea behind pharmacogenetics is that different people respond

differently to different drugs depending on their own individual chemistry.

Depending on your genes, one version of a drug may be more effective,

another less so.

 

Doctors are already beginning to incorporate this sort of information into

the prescription of certain powerful drugs, and they will do so more and

more as our understanding of genes grows.

 

Just as pharmacogenetics tailors medical intervention to individual genetic

profiles, a new field of " social-intervention genetics " could be tailored to

individual genetic profiles.

 

For example, other things being equal, society would get the most for its

social intervention buck by specifically offering certain social welfare

programs to those with the predisposing form of the MAO-A gene.

 

Genetic information should never be used to dictate who gets to (or, worse,

doesn't get to) reproduce; nor should society mandatorily impose

intervention where it is not wanted. But by helping to make social

interventions available to those who need them most, our growing

understanding of nature could help us get the most out of nurture.

2004, Newsday, Inc.