Researchers from around the world have launched a three-year project aimed at identifying genes that are responsible for such common illnesses as cancer, heart disease and diabetes. The effort is an outgrowth of the Human Genome Project.
The international Human Genome Project produced a genetic road map unveiled two years ago, describing the arrangement of chemical building blocks in each cell that regulates how humans function. But because the genome, or collection of genes, is so vast, researchers can only guess where to look within the blueprint for proteins that may play a role in illness.
The $100-million International HapMap Project, described as the next phase of the Human Genome Project, is a refinement. Fifteen teams of researchers in the United States, China, Canada, England, and Japan will attempt to identify so-called haplotypes, or groups of genes that are passed from one generation to the next.
David Altshuler of the Whitehead Center for Genome Research at Harvard Medical School in Cambridge, Massachusetts, heads one of the research groups working on HapMap.
Dr. Alschuler says one of the main goals of the Human Genome Project is to help understand the inherited basis of human disease, that is, why some people get diabetes or heart disease and others do not. That means cataloging the minute genetic differences between individuals.
Researchers think there are about ten-million genetic differences throughout the human genome that play a role in disease. One way to find the haplotypes is to search for them individually, an extremely time-consuming and expensive project. Or Dr. Altschulter says researchers can look for clusters or blocks of haplotypes and construct a map.
"The people who would get one particular variation would have a whole series of variations next to each other called a haplotype that they would inherit in common," he said. "And so in a sense the haplotype map is just a way to simplify this process of genetic studies."
Experts say that 99.9 percent of the population is genetically identical, having emerged from Africa between 10,000 and 100,000 years ago. It's the .1 percent difference in our DNA, or genetic material, that researchers focus on to learn more about disease.
Researchers think they will be able to create a map of all ten million haplotypes in the human genome testing between 200 to 400 blood samples drawn from Europe, Africa and Asia.
Tom Hudson, the head of Montreal's Genome Center at McGill University in Canada, which will analyze ten percent of the data for the HapMap project, says researchers will pinpoint blocks of haplotypes, or genetic markers, that disease researchers can consult once the map is finished.
"What we're going to identify is the right set of markers which can be used to test every block across the genome," he said. "So, if someone works in hypertension or diabetes, they need to go and test these markers that we've developed in terms of this project in their cohorts of people with hypertension compared to people without hypertension, and the same thing for diabetes and cancer and so on."
The Whitehead Institute's David Altschuler would like to see peoples' genetic susceptibility to disease put on the same mantle as the risk due to environmental factors, such as the increased likelihood that they'll get lung cancer if they smoke cigarettes. Dr. Altschuler thinks HapMap will do that.
"What we're talking about here actually is genetic exposure," he said. "That is, in addition to the environmental exposures that people have studied and will continued to study, we're saying here are the common genetic variations that might influence disease. And they'll be used in the same kind of association studies, epidemiologic studies, to ask are any of these variations correlated with disease. And if they are, then they become important targets for developing diagnostics and new therapies."
The HapMap project is scheduled to take three years to complete, although researchers hope to finish it sooner.