Pubdate: Sat, 10 Feb 2001
Source: Reuters
Copyright: 2001 Reuters Limited
Author: Patricia Reaney

GENE ROADMAP HOLDS DIRECTIONS TO ADDICTION, CANCER

LONDON (Reuters) - Like tourists poring over a map to find their way around 
an unknown city, scientists will be scrutinizing the sequencing of the 
human genome published on Monday for directions to the causes of disease.

The human genetic map, or book of life, isn't completely finished. A few 
major roads or chapters are still missing, but it is already showing 
researchers new routes to understanding what makes us who we are.

"It essentially provides a roadmap of the genes that are present in 
humans," Eric Nestler, of the University of Texas Southwestern Medical 
Center in Dallas, said in a telephone interview.

"The way to look at the genome sequence is not as an end result in itself 
but more as a road map to help us identify genetic abnormalities that 
comprise risk for addiction and many other diseases."

Like cancer and heart disease, addiction to alcohol and drugs can be 
inherited. Medical research suggests that about 50 percent of the risk of 
addiction is genetic.

"That would make addiction more heritable than diseases we commonly think 
of as genetic, such as adult onset diabetes or common hypertension," 
Nestler, the head of the department of psychiatry at the university, added.

But so far scientists haven't been able to identify any genetic 
abnormalities in humans that contribute to the risk of addiction in humans.

About 100 genes and their products have been shown to influence the process 
by which animals become addictive. Nestler believes the sequencing of the 
human genome, as well as the completed genomes of the mouse and rat which 
are expected soon, will narrow the search.

Profound Implications For Addiction

When the genes are found, he predicts they will have profound implications 
for preventing addiction and treating it.

People at risk could be targeted for more intense intervention to protect 
them from becoming addicted to alcohol or drugs, and those who already are 
could be provided with more effective treatments than are currently available.

"It is only when you understand a syndrome biologically and identify the 
root causes of the illness can you identify truly definitive treatments," 
Nestler said.

The destinations, or diseases, will be different but Nestler said the 
routes to get to the cause of them will be the same and will be mapped out 
in the genome sequence. Like addiction, cancer -- the most common genetic 
disease -- has it origins in DNA.

"All cancers are caused by abnormalities in DNA sequence," said Dr. Michael 
Stratton, the head of Britain's Cancer Genome Project.

One in three people in the western world will develop cancer and one in 
five will die from the disease, so the search to find the maybe 20 abnormal 
genes in any of the 200 types of cancer is a daunting task, but one that 
will be facilitated by the genome sequence.

Stratton, who was one of the scientists who identified the BRCA2 breast 
cancer gene, and his team have been comparing the draft human genome and 
cancer genome sequences for new cancer genes.

He said the finished sequence of the human genetic code will be a 
structural framework for a new generation of massive-scale comparisons of 
cancer cell and normal genomes.
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