“I thought you knew how the Bell worked, the genes it affected,” Kate said.
“We thought so too. We made two critical mistakes. The first was that our sample size was too small. The second was that we were studying bodies with direct contact with the Bell, never re-transmission. The Bell itself doesn’t emit an infectious agent: there’s no virus or bacteria. It emits radiation. Our working theory has been that the Bell radiation causes a mutation in an endogenous retrovirus, essentially reactivating an ancient virus that then transforms the host by manipulating a set of genes and epigenetic tags. We believe this ancient virus is the key to everything.”
Kate held her hand up. She needed to process. Martin’s theory, if true, was incredible. It indicated a completely new kind of pathogen and even a new pathogenesis—radioactive, then viral. Was it possible?
Retroviruses are simply viruses that can insert DNA into a host’s genome, changing the host at a genetic level. They’re a sort of “computer software update.” When a person contracts a retrovirus, they are essentially receiving a DNA injection that changes the genome in some of their cells. Depending on the nature of the DNA inserted, getting a virus could be good, bad, or benign, and since every person’s genome is different, the result is almost always uncertain.
Retroviruses exist for one purpose: to replicate, to produce more of their own DNA. And they are good at it. In fact, viruses make up the majority of all the genetic material on the planet. If one added together all the DNA from humans, every other animal, and every single plant—every non-viral life form on the planet—that sum total of DNA would still be less than all the viral DNA on Earth.
Viruses didn’t evolve to harm their hosts—in fact they depend on a living host to replicate, and that’s exactly what they do: find a suitable host and live there, replicating benignly, until the host dies of natural causes. These reservoir hosts, as scientists refer to them, essentially carry a virus without any symptoms. For example, ticks carry Rocky Mountain spotted fever; field mice, hantavirus; mosquitoes, malaria, West Nile virus, Yellow fever and Dengue fever; black rats, bubonic plague; pigs and chickens, flu.
Humans are actually reservoir hosts for countless bacteria and viruses that haven’t even been classified yet. About twenty percent of the genetic information in the nose doesn’t match any known or cataloged organism. In the gut, forty to fifty percent of all the DNA is from bacteria and viruses that have never been classified. Even in the blood, up to two percent is a sort of “biological dark matter.” In many ways, this biological dark matter, this sea of unknown viruses and bacteria, is the ultimate frontier.
Almost all viruses are harmless until they jump to another host—a life form different from their natural hosts. The virus then combines with a completely new genome and causes a new and unexpected reaction—an illness.
That was the ultimate danger with viruses, but Martin wasn’t talking about these infectious viruses that entered a human body from the outside; he was describing the activation of a past infection, a dormant set of viral DNA that originated inside the human body, buried inside the genome. It was like contracting an infectious virus from oneself—a sort of DNA Trojan horse that activated and began to wreak havoc on the body.
These human endogenous retroviruses (HERVs), as they are known, are essentially “viral fossils”—the remnants of past infections that changed the host genome, were integrated with the DNA of the host’s sperm, and were transmitted to future generations. Scientists had recently discovered that up to eight percent of the entire human genome was composed of endogenous retroviruses. These fossil records of past viral infections also appear in our closest genetic relatives, living and dead: chimpanzees, Neanderthals, and Denisovans. They had been infected with many of the same viruses we had.
Kate turned the idea over in her mind. Endogenous retroviruses had been considered inert and essentially part of a large group of “junk DNA” in everyone’s genome. These retroviruses were not infectious, but they did influence gene expression and were passed on to future generations. Scientists had recently begun to consider the possibility that endogenous retroviruses could play a role in autoimmune diseases such as lupus, multiple sclerosis, Sjögren’s syndrome, even cancer. If the virus behind the Atlantis Plague was an endogenous retrovirus, it would mean…
“You’re saying the entire human race is already infected. That we were infected the day we were born—that the virus behind the Atlantis Plague is already part of our DNA.” She paused. “The Bell and the bodies from it only activated a dormant virus.”