'Junk' DNA Reveals 100 Genetic Variants Implicated in Cancers

Scientists may have made a breakthrough when it comes to detecting disease-causing genetic mutations. They've found nearly 100 genetic variants implicated in the development of cancers such as breast cancer and prostate cancer. The new method for finding these variants could potentially be applied to find any disease-causing variant in the non-coding regions of the genome.

Unlike the coding region of the genome, where our 23,000 protein-coding genes lie, the non-coding region is poorly understood. Even though it makes up 98 percent of our genome, scientists have long wondered what this "junk" DNA is used for. Recent studies have actually indicated that these non-coding regions are used in the regulation of proteins; using this as a jumping off point, researchers decided to investigate a bit further.

The new method relies on identifying DNA regions within non-coding DNA, the major part of the genome that's not translated into a protein. Mutations here can cause diseases such as cancer.

"Our technique allows scientists to focus in on the most functionally important parts of the non-coding regions of the genome," said Mark Gerstein, one of the researchers, in a news release. "This is not just beneficial for cancer research, but can be extended to other genetic diseases too."

So how exactly does this method work? The scientists used the full set of genetic variants from the first phase of the 1000 Genomes Project together with information about the non-coding regions generated by the ENCODE Project. They then identified regions that did not accumulate much variation.

The researchers found that some non-coding DNA regions showed almost the same low levels of variation as protein-coding genes. They called these "ultrasensitive" regions. Within these ultrasensitive regions, the scientists looked at specific single DNA letters that, when altered, caused the greatest disturbance to the genetic region. If this non-coding, ultrasensitive region is central to a network of many related genes, variation can cause a great knock-on effect, resulting in disease.

"Our method is a practical and successful way to screen for purifying selection in non-coding regions of the genome using freely available data such as those from the ENCODE and 1000 Genomes Project," said Yali Xue, one of the researchers, in a news release. "It really shows the value of these large-scale open access data-sets."

The findings reveal an effective tool for finding variations associated with different cancers. This could be hugs for detecting disease-causing variants in the non-coding regions of the genome.

The findings are published in the journal Science.