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Scientists Unveil Genetic Blueprint Pinpointing Disease Genes

An international group of scientists has unveiled what's being called a "milestone for medical research." It's a genetic road map that should speed the discovery of genes that cause disease and assist in the development of new treatments. The so-called HapMap project is the outgrowth of the Human Genome Project unveiled in April 2003.

The fruit of the Human Genome Project was a rough draft unlocking the alphabet code of the 20,000 genes in our DNA.

These genetic building blocks, or genetic sequence, as it's known, are attached to two thread-like chromosomes wound tightly inside each cell. They determine all physical characteristics, including whether someone develops a disease.

Francis Collins, head of the U.S. National Institutes of Health's Human Genome Institute, was among those announcing the publication of HapMap, a three year effort by an international consortium of 200 scientists to catalog genetic variation responsible for human illness.

"The [human] genome project gave us the letters of the DNA code that we all share," he explained. "But variety is the spice of life. HapMap investigates those spelling differences in the human instruction book that predispose some to diabetes, others to heart disease, others to cancer, others to mental illness, others to asthma. It's a long list."

Experts say any two people are 99.9 percent genetically identical. People differ within that .1 percent, a fraction that scientists say helps explain why some people are more likely to develop a disease than others or have a better response to a drug than someone else.

Scientists say HapMap, when completed, could lead to the identification by gene hunters of a single mutation out of three billion letters in the DNA code book that could, potentially, tip the balance in a person's developing a disease. Before HapMap, the search for disease genes could be slow at best.

Researchers from six countries, including China, Nigeria, and the U.S., produced the HapMap from blood samples collected from 269 volunteers around the world.

Investigators plan to continue their work by collecting more samples from a greater global cross-section, and analyze them starting in the middle of next year.

Charles Rotimi of Howard University in Washington DC is a visiting professor from Nigeria's University of Ibadan. Dr. Rotimi will oversee the collection of blood samples.

"So, our goal, is for HapMap to eventually benefit all human populations in terms of understanding health;" he explained, "and not just the majority population that happen to have the monetary resources. In this regard, we are committed to global inclusion."

In HapMap's second phase, researchers are using improved technology to identify more genetic variations.

Two articles describing the first phase of the HapMap project are published in the October 27 issue of the journal Nature.