Toronto, July 16 (Inditop.com) New research by Canadian scientists is set to turn upside down the DNA theory which says that every cell in the body is identical to every other cell.
Current genetic studies to know the causes of many diseases involve blood samples from the patients on the presumption that all cells in the body are same.
But a new study by researchers at Montreal’s McGill University has found differences in cells from blood and body tissue.
Researchers also say that except for cancer, samples of diseased tissue are difficult or even impossible to take from living patients.
The vast majority of genetic samples used in large-scale studies today come in the form of blood, but the researchers have found that blood and tissue cells do not match genetically.
Thus, the current expensive genomic studies may prove to have been essentially flawed from the outset, according to the new study.
The discovery came to light when the researchers were studying the genetic causes of abdominal aortic aneurysms (AAA), which is one of the rare vascular diseases where tissue samples are removed as part of patient therapy.
But when the researchers compared the tissue samples, they found major differences between BAK genes in blood cells and tissue cells coming from the same individuals, with the suspected disease ‘trigger’ residing only in the tissue. BAK genes control death cells.
The same differences were later found in samples from healthy individuals, a university statement said Wednesday.
“In multi-factorial diseases other than cancer, usually we can only look at the blood,” said Bruce Gottlieb, a geneticist at McGill’s University’s Centre for Translational Research in Cancer.
“Traditionally, when we have looked for genetic risk factors for, say, heart disease, we have assumed that the blood will tell us what’s happening in the tissue. It now seems this is simply not the case. From a genetic perspective, therapeutic implications aside, the observation that not all cells are the same is extremely important. That’s the bottom line,” he said.
“Genome-wide association studies were introduced with enormous hype several years ago, and people expected tremendous breakthroughs. They were going to draw blood samples from thousands or hundreds of thousands of individuals, and find the genes responsible for disease.
“Unfortunately, the reality of these studies has been very disappointing, and our discovery certainly could explain at least one of the reasons why,” added Gottlieb.
Co-researcher Morris Schweitzer said: “This (discovery) will probably have repercussions for vascular disease in general. We have not yet looked at coronary or cerebral arteries, but I would suspect that this mutation may be present across the board.”
He said their discovery may lead to new treatments for vascular disease in the near future.
“The timeline might be five to 10 years. This is the first step, but it’s an important step,” said the Canadian researcher.
The study appears in the July issue of the journal Human Mutation.
