The Lurker: How a Virus Hid in Our Genome Ffor Six Million Years
19th December 2014
HIV belongs to a class of viruses called retroviruses. They all share three genes in common. One, called gag, gives rise to the inner shell where the virus’s genes are stored. Another, called env, makes knobs on the outer surface of the virus, that allow it to latch onto cells and invade them. And a third, called pol, makes an enzyme that inserts the virus’s genes into its host cell’s DNA.
It turns out that the human genome contains segments of DNA that match pol, env, and gag. Lots of them. Scientists have identified 100,000 pieces of retrovirus DNA in our genes, making up eight percent of the human genome. That’s a huge portion of our DNA when you consider that protein coding genes make up just over one percent of the genome.