Neanderthal Viruses Found in Modern Humans

Ancient viruses from Neanderthals have been found in modern human DNA by researchers at Oxford University and another university. 

Around 8% of human DNA is made up of 'endogenous retroviruses' (ERVs), DNA sequences from viruses which pass from generation to generation. This is part of the 90% of our DNA with no known function, sometimes called 'junk' DNA.
'I wouldn't write it off as "junk" just because we don't know what it does yet,' said Dr Gkikas Magiorkinis, an MRC Fellow at Oxford University's Department of Zoology. 'Under certain circumstances, two "junk" viruses can combine to cause disease -- we've seen this many times in animals already. ERVs have been shown to cause cancer when activated by bacteria in mice with weakened immune systems.'
Dr Gkikas and colleagues are now looking to further investigate these ancient viruses, belonging to the HML2 family of viruses, for possible links with cancer and HIV.

'How HIV patients respond to HML2 is related to how fast a patient will progress to AIDS, so there is clearly a connection there,' said Dr Magiorkinis, co-author of the latest study. 'HIV patients are also at much higher risk of developing cancer, for reasons that are poorly-understood. It is possible that some of the risk factors are genetic, and may be shared with HML2. They also become reactivated in cancer and HIV infection, so might prove useful as a therapy target in the future.'