The genomes of humans as well as of Neandertals and Denisovans contain retroviruses that inserted themselves into the sequence. Last year, the New Scientist reports, a group at Albert Einstein College of Medicine in New York searched through the genomes of the ancient hominins for such viruses. As the team led by Jack Lenz reported in Current Biology, they unearthed 14 retroviruses insertion sites, none of which they saw in modern humans.
However, New Scientist points out, a new study, also in Current Biology, from a separate group led by Robert Belshaw at Plymouth University and Gkikas Magiorkinis at the University of Oxford did find those some of those retroviral gene sequences in modern humans.
This group searched through the genomes of cancer patients, and found seven of those retroviral sequences. The team suggests that it was able to find these retroviral sequences — and suspect it may be able to find others — because it looked in a number of people while the Lenz group examined the reference genome and those sections of the references happened to be from people who lacked the insertions.
Belshaw and Magiorkinis tell the New Scientist that they are now looking into how common these viruses are and whether they are ever active. "Within the next five years, we should be able to say for sure whether these ancient viruses play a role in modern human diseases," Belshaw says.