OK, actually, just *part* virus:
People may not be quite the humans they think they are. Or so suggests new research showing that the human genome is part bornavirus.
Bornaviruses, a type of RNA virus that causes disease in horses and sheep, first inserted their genetic material into ancestral human DNA at least 40 million years ago, the study shows. The findings, published January 7 in Nature, provide the first evidence that RNA viruses other than retroviruses (such as HIV) can stably integrate genes into host DNA. The new work may help reveal more about the evolution of RNA viruses as well as their mammalian hosts.
“Our whole notion of ourselves as a species is slightly misconceived,” says Robert Gifford, a paleovirologist at the Aaron Diamond AIDS Research Center, affiliated with Rockefeller University in New York City. Human DNA includes genetic contributions from bacteria and other organisms, and humans have even come to rely on some of these genes for basic functions like fighting infections.