This Is MS Multiple Sclerosis Community: Knowledge & Support

Some good progress in decoding DNA...



New map of DNA variations should hasten discovery of disease-related genes

Canadian Press - October 26, 2005 - International researchers, including Canadians, have developed a map of the minute DNA variations that differentiate one person from another, a catalogue that will help scientists tease out the genes that underlie such diseases as diabetes, cancer and heart disease.

"It's a big turning point in the field of human genetics and understanding risk factors to disease," said Dr. Tom Hudson, director of the McGill University and Genome Quebec Innovation Centre in Montreal and one of the project's leading researchers.

"It's like putting someone out in space for the first time," Hudson said from Salt Lake City, Utah, where completion of Phase 1 of the mapping project was announced Wednesday. "It's not yet to the moon or to another planet, but it is a major milestone."

The "HapMap," so-called because it details DNA variations known as haplotypes, will allow scientists to study every region of the entire human genome by keying in on specific areas of chromosomes where these differences are now known to exist, said Hudson.

Likening these areas to bins containing specific genes - there are about 100,000 of the "containers," all told - Hudson said scientists will be able to look bin by bin to see which ones are "more associated with asthma or colon cancer or multiple sclerosis or nothing."

Researchers say the HapMap is a tool that will help them locate those genes that cause a host of diseases, allowing them to develop better ways to predict, diagnose and treat the conditions both in populations and individual patients.

Hudson said HapMap is already reaping scientific benefits.

His team at McGill, in conjunction with other researchers, found the gene that protects some Vietnamese and Brazilian families from leprosy; scientists recently announced the discovery of a gene associated with macular degeneration, the leading cause of vision loss in the elderly.

Other international researchers are using the HapMap to seek the genetic basis for autism, asthma and multiple sclerosis, to name a few. A group of Ontario patients is being studied using HapMap to find genes linked to colon cancer.

The $138-million US HapMap project involved more than 200 scientists from Canada, China, Japan, Nigeria, the United Kingdom and the United States. Canada provided one-tenth of the funding and Hudson's team was responsible for 10 per cent of the work, mapping haplotypes in 1 1/2 of 22 chromosomes analyzed. (The Y chromosome, the 23rd, has little variation).

Human DNA is made up of about three billion building blocks in various combinations that form genes. The genetic makeup of any two unrelated people is 99.9 per cent the same. It is in the other 0.1 per cent that variations arise.

The HapMap, described in Thursday's issue of the journal Nature, is a catalogue of patterns of these variations found after the researchers analyzed DNA in blood from 269 people from Nigeria, Beijing, Tokyo and Utah. These participants are said to be representative of the world's populations.

http://www.canada.com/health/story.html ... a7052197d9