Tools, Not Teeth, Telltale Clue to Fewer Viral DNA Remnants?

Scientists have found people’s genes haven’t retained as many fragments of viral DNA as other mammals, maybe due in part to our adoption of tools in lieu of teeth during conquest. Thus, exposure to viruses lurking in the blood may have been lessened. This is not to say people don’t harbor bits of DNA from viruses that bugged our ancestors millions of years ago, we do. Retroviruses can penetrate mammalian sperm or egg, where their genetic code becomes part of the mammal’s genome, passed down through the generations. However, these ‘endogenous retroviruses’ (ERVs) seem harmless to humans, while they may be hazardous to other mammals, even causing cancer. The question of why these so-called retroviruses don’t harm humans roused researchers from the University of Oxford and Plymouth University, UK, and the Aaron Diamond AIDS Research Center, New York—who investigated how often these so-called “viral fossils” seem to have been rolled in to the human genome versus other mammals with fur or fins. Researchers looked at the genetic signature of the two edges of the virus, which are the same when the virus first invades the genome, but change as they accumulate random mutations over time. Their findings, in an article titled “The decline of human endogenous retroviruses: extinction and survival,” and published in the journal Retrovirology, are found here: bit.ly/1zQnOep For another take on this topic, read Carl Zimmer’s article in National Geographic’s Phenomena, titled “Our Inner Viruses: Forty Million Years In the Making,” at bit.ly/1DupSGe Image: retroviruses [Photo credit: Wikipedia]