http://fivethirtyeight.com/features/what-percent-virus-are-you/
DEC 14, 2016 AT 10:43 AM
What Percent Virus Are You?
By Hannah Moots
—
Since viruses cannot replicate on their own, they use the cells of the organisms they infect to make new copies of themselves. One type of virus, retroviruses, inserts a DNA copy of its RNA sequence into the host cell’s genome upon infection. If the virus inserts into a reproductive cell and that cell goes on to produce an offspring, the viral DNA gets passed on from parent to child as part of the genome.2 At this point, the virus is locked in and is passed on from generation to generation. These are called endogenous retroviruses, or ERVs, and this can happen in any type of organism that viruses infect, including humans.
More Science & Health
So yes, that means your genome is part virus. More than 100,000 sequences in the human genome3 originated this way. Scientists have recognized the presence of viral DNA in the human genome for decades, but it wasn’t until after the human genome was sequenced, or mapped, in 2003 that they could study just how much of our DNA comes from viruses. While the viral sequences in the human genome today originated from about 50 infection events in the distant past that were passed on as described above, the viral sequences were copied and reinserted hundreds, sometimes thousands, of times.
—