Breathless: The Scientific Race to Defeat a Deadly Virus

by David Quammen

But if the host cell is lucky, maybe the virus simply settles into this cozy outpost, either going dormant or back-engineering its genome into the host’s genome, and bides its time. This second trick is what retroviruses, such as HIV-1, do. It carries many implications for the mixing of genomes, for evolution, even for our sense of identity as humans. Eight percent of the human genome consists of viral DNA that has been inserted into our lineage, over millions of years, in this way. That’s a very different take on the trope of “I, Virus.” Both you and I, as well as Tony Fauci and everyone else, are 8 percent viral in our genomes. And that doesn’t even count the viruses of the human microbiome, carried in our bellies and on our skin and elsewhere, but not in our genomes like the retroviral DNA.