Scientists have linked a region of junk DNA, the 98 per cent or so of the genome that does not code for proteins, to the risk of developing at least one form of heart disease.
The research, published online in Nature, drew on previous genome-wide association studies that linked a non-coding stretch of chromosome 9p21 with coronary artery disease (CAD) and showed that people who carry certain single nucleotide mutations in this stretch of DNA have an increased chance of developing the disease.
Principal investigator and geneticist Len Pennacchio of the Lawrence Berkeley National Laboratory in Berkeley, California, based the study on the equivalent chromosome in mice and found a potential mechanism for how the region of non-coding DNA might increase the risk of heart disease.
Pennacchio said: "We were really interested in understanding how this purely non-coding interval leads to CAD, so we thought, 'Let's delete it and see what happens'."
He continued: "We did, and found that the expression of two genes nearly 100,000 base pairs away from the deletion dramatically decreased in mice."
But the expert pointed out: "How this translates into humans, we don't know yet."
Pennacchio added: "The fact that this non-coding region works on genes over 100,000 base pairs away goes to show that non-coding DNA can play important roles in common human disorders.
"We want to globally understand what fraction of human diseases are due to variation in the coding versus non-coding regions. That's a huge unanswered question as we continue into the post-genomic era."
Cardiovascular specialist Ruth McPherson of the University of Ottawa Heart Institute in Ontario, Canada, who led a genome-wide association study on CAD1, said: "This study brings the nderstanding of 9p21 and CAD risk to another level."