Journal information: Current Biology Scientists have known for many years that some viruses can impact not just the general biology of animals (and humans) but can make their way into their genome, causing changes to strands of DNA. Those changes can then be passed on to offspring. To date, no such strands have ever been found to cause ailments in humans, however.In June of 2012, another team of researchers discovered changes that had come about in Neanderthal and Denisovan DNA due to an ancient retrovirus. The virus left evidence of its existence in a parts of the genome known as “junk” sequences—so named because they don’t hold any information related to creating proteins—they don’t appear to do anything. That team found 14 unique instances of such virus evidence. Intrigued, the team then looked to see if any of the 14 existed in modern human DNA. Their cursory inspection didn’t find any matches.In this new research, the team in Britain took a much closer look, and in doing so, found 7 matches—but only in cancer patients. More specifically, they took DNA samples from 67 people, all of whom had some form of cancer. In studying the samples, the researchers found that every single one of the cancer patients had seven of the virus sequences that matched those found in Neanderthal and Denisovan DNA last year.The findings by the team suggest that there might be a link between people with the ancient virus information stored in their junk sequences and a tendency to get cancer. The researchers suggest that because of what they’ve found, it seems likely that the other seven retroviruses found by the team last year in Neanderthal and Denisovan DNA exist in the genomes of other people alive today. That could mean that such people have a higher incidence of other unknown medical problems. More research will have to be conducted, though the team acknowledges it could take a lot of time as the process could potentially involve examining the genomes of groups of people afflicted with any number of ailments. © 2013 Phys.org (Phys.org) —An ancient retrovirus that altered the DNA of Neanderthals and Denisovans has now been found to have left alterations in modern human DNA as well—in some cancer patients. The team of researchers from the U.K. that made this startling discovery has written about what they’ve uncovered in a paper published in the journal Current Biology.