Our Viral Symbiotes

About 8% of our DNA may have come from ancient viruses that infiltrated our cells, where they established permanent residence.

Viral "Fossils" in Our DNA

The human genome includes 100,000 pieces of "ancient viral DNA." Recent studies of what function, if any, this "fossil" DNA might perform in our bodies suggest that it may play a vital role in boosting our immune systems. Amazingly, viruses that invade our cells sometimes not only become part of our chromosomes but become inheritable. The article summarizes the process thusly:

"When a type of virus known as a retrovirus infects a cell, it converts its RNA into DNA, which can then become part of a human chromosome. Once in a while, retroviruses infect sperm and egg cells and become 'endogenous,' meaning they are passed down from generation to generation."

In science-fiction treatments of traditional monsters such as vampires and werewolves, this ability of some retroviruses could be invoked to rationalize how a naturally evolved creature of a different species could convert a human victim—or willing host—into a member of the "monster" species.

When Walt Whitman declared, "I contain multitudes," he wrote truer than he could have suspected. That quote features in the title of a book by Ed Yong, I CONTAIN MULTITUDES: THE MICROBES WITHIN US AND A GRANDER VIEW OF LIFE, about microbiomes inside animals and especially humans, in the context of a vision of our bodies as "living islands" with millions of inhabitants.

On a totally different topic, but harking back to some of my earlier posts, here is a detailed article about the intelligence of octopuses, to which I've alluded more than once in the past. As the article says, they're probably the closest to intelligent aliens of any species we currently know. Cool!

Another Path to Intelligence

Margaret L. Carter

Carter's Crypt

Undersea Aliens

Peter Godfrey-Smith, a professor at the University of Sydney and City University of New York, believes the octopus is the closest thing to an alien living on Earth with us. Octopuses "are the most complex animal with the most distant common ancestor to humans."

Octopus Intelligence

In many ways, octopuses seem as different from us as an advanced creature can be and evolve on the same planet. They have three hearts and blue, copper-based blood. They have the ability to change color, which they use for camouflage. Suppose we encountered an extraterrestrial species of intelligent cephalopods who communicated by waves of colors? We would have to learn a whole new mode of language. Octopuses "developed eyes, limbs, and brains via a completely separate route" from us. With neurons distributed through their bodies instead of solely localized in their heads, we might say they have brains in their arms. They show considerable intelligence, such as in escaping from confinement, and they can tell human individuals apart. Octopuses seem to play, another sign of high intelligence. They also display curiosity, which Godfrey-Smith thinks may be evidence of subjective consciousness. If so, consciousness has appeared separately at least twice on Earth.

It has been suggested that a possible reason why they haven't evolved even higher intelligence springs from their reproductive cycle. Male octopuses typically die soon after mating, and females don't live long past the hatching of their offspring. Therefore, adults don't survive to pass on knowledge and skills to their young. Octopuses can't have much of a culture, if any. Their solitary lifestyle (aside from mating) is probably another factor, since gregarious species tend to be more intelligent than solitary ones; interactions with other members of one's species in a group require mental flexibility.

Godfrey-Smith makes the optimistic assumption that the evolution of consciousness at least twice on Earth implies consciousness isn't a rare fluke, but a potentially common natural development. That assumption, if valid, bodes well for the discovery of sapient beings elsewhere in the universe. If a race of giant octopuses on another planet—perhaps one mainly or entirely covered by water—overcame the disadvantages of their short, solitary lives, maybe by evolving a long-lived, asexual caste responsible for the care and education of the young, they could create something we would recognize as a culture.

Margaret L. Carter

Carter's Crypt