An Ancient Virus May Be Responsible for Human Consciousness… Ancient Viruses Are Buried in Your DNA

Viruses are responsible for human consciousness and higher thinking. 😆😂🤣 That is the funniest thing I’ve read this year!

You know where I’m going with this avenue of research don’t ya! 🙄😉

An Ancient Virus May Be Responsible for Human Consciousness

By Rafi Letzter

First Published 2 years ago

(Image credit: Shutterstock)

You’ve got an ancient virus in your brain. In fact, you’ve got an ancient virus at the very root of your conscious thought.

According to two papers published in the journal Cell in January, long ago, a virus bound its genetic code to the genome of four-limbed animals. That snippet of code is still very much alive in humans’ brains today, where it does the very viral task of packaging up genetic information and sending it from nerve cells to their neighbors in little capsules that look a whole lot like viruses themselves. And these little packages of information might be critical elements of how nerves communicate and reorganize over time — tasks thought to be necessary for higher-order thinking, the researchers said.

Though it may sound surprising that bits of human genetic code come from viruses, it’s actually more common than you might think: A review published in Cell in 2016 found that between 40 and 80 percent of the human genome arrived from some archaic viral invasion. [Unraveling the Human Genome: 6 Molecular Milestones]

That’s because viruses aren’t just critters that try to make a home in a body, the way bacteria do. Instead, as Live Science has previously reported, a virus is a genetic parasite. It injects its genetic code into its host’s cells and hijacks them, turning them to its own purposes — typically, that means as factories for making more viruses. This process is usually either useless or harmful to the host, but every once in a while, the injected viral genes are benign or even useful enough to hang around. The 2016 review found that viral genes seem to play important roles in the immune system, as well as in the early days of embryo development.

But the new papers take things a step further. Not only is an ancient virus still very much active in the cells of human and animal brains, but it seems to be so important to how they function that processes of thought as we know them likely never would have arisen without it, the researchers said.

The Arc gene

Shortly after a synapse fires, the viral gene known as Arc comes to life, writing its instructions down as bits of mobile genetic code known as RNA, the researchers found. (A synapse is the junction between two neurons.)

RNA is DNA’s messenger and agent in the world outside the cell’s nucleus. A single-strand copy of code from DNA’s double helix, it carries genetic instructions to places they can be useful. (And, interestingly, viruses tend to store their genetic code in RNA, rather than in DNA.)

Following the Arc RNA’s instructions, the nerve cell builds “capsids” — virus-like envelopes — around it. Those envelopes let it travel safely between cells, and it does just that, entering neighboring neurons and passing its packet of genetic information along to them, according to the studies.

It’s still unclear what that information does when it arrives in a new cell, but the researchers found that without the process functioning properly, synapses wither away. And problems with the Arc gene tend to show up in people with autism and other atypical neural conditions, the researchers said.

In a companion article, two experts who were not involved in the 2018 papers (the same two experts, in fact, behind the 2016 review) wrote that this process offers the best explanation yet for how nerve cells exchange the information necessary to reorganize themselves in the brain over time.

“These processes underlie brain functions ranging from classical operant conditioning to human cognition and the concept of ‘self,'” they wrote. (Classical and operant conditioning are simple forms of reward and punishment-based learning in animals and humans.)

Bizarrely, Arc seems to have made the jump from virus to animal more than once. The researchers found that Arc genes in humans and other four-limbed creatures seem to be closely related to one another. The Arc genes in fruit flies and worms, however, seem to have arrived separately.

The next step for this research, the outside experts wrote in the companion article, is to bring experts in neuroscience and ancient viruses together to work out the mechanisms for just how Arc arrived in the genome, and exactly what information it’s passing between our cells today.

Originally published on Live Science.

Ancient Viruses Are Buried in Your DNA

A human embryo at 45 days. Scientists have learned that a protein called Hemo, made by a fetus and the placenta, is produced from viral DNA that entered our ancestors’ genomes 100 million years ago.Credit…Omikron, via Science Source

By Carl Zimmer

  • Oct. 4, 2017

In July, scientists reported that a strange protein courses through the veins of pregnant women. No one is sure what it’s there for.

What makes this protein, called Hemo, so unusual is that it’s not made by the mother. Instead, it is made in her fetus and in the placenta, by a gene that originally came from a virus that infected our mammalian ancestors more than 100 million years ago.

Hemo is not the only protein with such an alien origin: Our DNA contains roughly 100,000 pieces of viral DNA. Altogether, they make up about 8 percent of the human genome. And scientists are only starting to figure out what this viral DNA is doing to us.

Aris Katzourakis, a virologist at the University of Oxford, and his colleagues recently published a commentary in the journal Trends in Microbiology in which they explored the possibility that viral genes that produce proteins like Hemo are affecting our health in a variety of unexpected ways.ADVERTISEMENT

Some of our ancient viruses may be protecting us from disease; others may be raising our risks for cancer, among other conditions. “It’s not an either-or — are these things good or bad? It’s a lot more complicated than that,” Dr. Katzourakis said in an interview. “We’re barely at the beginning of this research.”

Most of our viral DNA comes from one group in particular: retroviruses, a group that includes HIV.

A retrovirus invades a host cell and inserts its genes into that cell’s DNA. These viral genes co-opt the cell’s machinery, using it to make new viruses that escape to infect more cells.

If a retrovirus happens to infect an egg or sperm, its DNA can potentially be passed to the next generation and the generation after that. Once retroviruses become inherited stowaways, scientists refer to them as endogenous retroviruses.

At first, endogenous retroviruses coax cells to make more retroviruses that can infect other cells. But over the generations, the viral DNA mutates, and endogenous retroviruses eventually lose the ability to infect new cells.ADVERTISEMENT

Even after being hobbled, these endogenous retroviruses can still sometimes make their proteins. And they can also reproduce, after a fashion. They can force cells to make copies of their DNA, which are inserted back in the cell’s own genome.

After a single infection, an endogenous retrovirus may build up hundreds of copies of itself in its host’s DNA.

Some endogenous retroviruses are unique to humans, but others are found in a variety of species. In January, Dr. Katzourakis was a co-author on a study showing that one retrovirus common in mammals also is present in fish like cod and tuna. Retroviruses, that study indicated, were invading our marine ancestors 450 million years ago — or even earlier.

Just as we have defenses against free-living viruses, we have also developed defenses against endogenous retroviruses. Our cells can coat their DNA with molecules that suppress viral genes, for example.ADVERTISEMENT

But sometimes these viral genes manage to switch on anyway. In many kinds of tumor cells, for instance, scientists find proteins produced by endogenous retroviruses. That discovery has fueled a long-running debate: Do endogenous retroviruses help cause cancer?

Recent studies suggest they can. A team of French researchers engineered healthy human cells to make a viral protein found in many tumors and watched the cells grow in a petri dish.

The protein caused the cells to behave in some suspiciously cancer-like ways. They changed shape, as cancer cells do, becoming long and skinny. And they also started to move across the dish.

In addition, the viral protein caused the cells to switch on other genes that have been linked to cancer.ADVERTISEMENT

But John M. Coffin, a virologist at Tufts University, suspects there’s less to these viral proteins than meets the eyes. He speculates that in many cases, cancer cells make viral proteins only because they are switching on genes willy-nilly — both human and viral genes alike.

“Our starting position is that this is largely a chance event,” Dr. Coffin said.

But in certain cases, Dr. Coffin said, we have domesticated our viruses. We make proteins from endogenous retroviruses to carry out functions we depend on. Some endogenous retroviruses offer protection against other viruses, for example.

And some viral proteins are important for reproduction. Placentas make viral proteins, and scientists have found that some types, known as syncytins, fuse together placental cells, a crucial step in fetal development.

“My speculation is that without syncytins, mammal evolution would have looked very different,” Dr. Coffin said.ADVERTISEMENT

Five years ago, the French biologist Odile Heidmann and her colleagues went on a search for more endogenous retroviruses in the human genome.

Dr. Heidmann, who works at Gustave Roussy, a cancer research institute in Paris, discovered a stretch of viral DNA that had gone overlooked. She and her colleagues named it Hemo.

Dr. Heidmann was surprised to find versions of Hemo in other species. Among primates, the gene that makes this protein has barely changed over the ages.

Its consistency across many species shows that the gene and its protein must have an important job to do: “It isn’t simply a relic,” Dr. Heidmann said. Mutations to Hemo must have been harmful or even fatal to the unfortunate animals who had them.ADVERTISEMENT

The placenta produces Hemo, and so do cells in the early embryo itself. But so far Dr. Heidmann and her colleagues have not been able to figure out why.

“It’s very, very old, so it has to do something,” she said. It’s possible, she said, that Hemo proteins are a message from fetus to mother, dampening the mother’s immune system so that it doesn’t attack the fetus.

But there are other possibilities, too.

The early embryo is a hotbed of activity for endogenous retroviruses, recent studies have shown. To understand why embryonic cells make viral proteins, scientists have run experiments to see what happens when viral genes are silenced.

These experiments suggest that viral proteins help the embryo develop a variety of tissues.

Early on, the cells in an embryo can turn into any tissue. As these stem cells divide, they can lose this flexibility, committing to becoming one kind of cell or another. After that, cells typically shut down their viral genes.ADVERTISEMENT

Viral proteins appear to help keep stem cells from losing this potential. And Gkikas Magiorkinis of the University of Athens has speculated that this feature might have a sinister origin.

Viruses might have exploited embryos to make more copies of themselves. By keeping their hosts as stem cells for longer, the viruses were able to invade more parts of the embryo’s body.

“When the host grows, it will have copies in the retrovirus in most of its cells,” Dr. Magiorkinis said.

This strategy may do more than create more viruses. Stem cells can produce eggs and sperm in embryos. The viruses may be raising their odds of getting into the next generation.

In other words, early embryos may have come to depend on the tricks viruses use to manipulate them. “We’re exploiting a property that has evolved for the virus’s benefit,” Dr. Katzourakis said.

The Human Genome Is Full of Viruses

Your body requires viruses, but viruses don’t always require a body

Ben L. Callif

Ben L. CallifJan 3 · 6 min read

Viruses use cellular mechanisms of transcription and translation (turning DNA to RNA and RNA to proteins) to replicate themselves and infect all kinds of living things. Image Credit: Arizona State University

Viruses are amazing molecular machines that are much tinier than even the smallest cells. We often think of viruses like the flu, chickenpox, or herpes as “external” invaders, but viruses are more inherently associated with human life than we often realize. Even after recovering from an infection there will always be a piece of that virus encoded within your DNA. Approximately 8% of the human genome is made up of endogenous retroviruses (ERVs), which are viral gene sequences that have become a permanent part of the human lineage after they infected our ancient ancestors. And these endogenous retroviruses don’t just sit silently in the genome — their expression has been implicated in diseases like autoimmune disorders and breast cancer.

But endogenous retroviruses don’t only harm our health; they can also be extremely useful for human survival. For example, they play a very important role as an interface between a pregnant mother and her fetus by regulating placental development and function. It has been suggested that viruses are not only necessary for the existence of placental mammals, but also for the existence of life in general. Professor Luis P. Villarreal, the Founding Director of the Center for Virus Research at UC Irvine, says it like this“So powerful and ancient are viruses, that I would summarize their role in life as ‘Ex Virus Omnia’ (from virus everything).”

Viruses are powerful, ancient, and vital to our existence, but they are extremely simple constructions. They tend to be nothing more than a few pieces: a protein capsid, which is a simplistic and protective shell; a protein called a polymerase, which carries out most of the functions related to replicating the viral genome; and a sequence of nucleotides — either RNA or DNA — that encode for the previously mentioned viral proteins. The image below shows one of the ways that these viral components can be assembled into a unified whole. Unlike a human genome, a viral genome can be thought of as a self-contained model of the entire viral form. Within its RNA or DNA, a virus contains all the instructions necessary to create an entirely new body for itself and to replicate those same instructions. The simplicity and self-contained nature of viruses makes them phenomenal tools for biological engineering and medicine.

Viruses (specifically bacteriophages) as imaged with an electron microscope. Image Credit: Wikimedia Commons

Viruses are so simple that they don’t always need their own body to survive; they have circadian rhythms like all living things. We experience these rhythms through cycles of sleep and wakefulness, whereas viral rhythms occur as periods of dormancy between rounds of infection. Viruses don’t technically have a body during their dormant phase — they are nothing more than a string of letters in the book of the genome. But, as soon as something disturbs their sleep (like a mutation or a new virus invading the host) viruses can awaken and rebuild their physical bodies from a purely genetic form. When the wrong (or right, depending on your perspective) protein manages to leak out of a dormant viral gene, it is like the virus is suddenly awake again. A new physical body means that it has all the tools necessary to replicate.

Even beyond these rhythmic cycles, certain kinds of viruses don’t need a physical form at all. These disembodied viruses are called transposable elements, or transposons. True viruses have a body made from proteins, but transposons are mobile genetic elements — sequences of DNA that physically move in and out of genomes.For this reason, they are often referred to as “jumping genes.” Transposons do very much the same thing as true viruses, i.e. they copy and paste themselves throughout genomes. They are so similar to true viruses that some endogenous retroviruses (ERVs) are themselves transposons. As stated above, ~8% of the human genome is made up of ERVs, but nearly 50% of the human genome is made of transposons!Humans are basically just big piles of viral-like sequences.

Transposable elements (transposons) are sequences of DNA that literally jump in and out of the genome. Image Credit: Harvard University

Transposons have a disturbing capacity to disrupt important genes by inserting themselves into the DNA sequences. It’s like if a series of words in a book could physically move around from page to page — these words would have a high likelihood of jumping into the middle of a sentence, thereby making it nonsensical. Amazingly, transposons preferentially insert themselves into important and functional genes — as if those jumping words wanted to disrupt the most interesting parts of the book rather than the index or bibliography. This is a powerful evolutionary strategy, since transposons are much more likely to get “read” by a cell if they jump into the middle of an important (and therefore, active) gene.

Transposons can very easily mess up important genes that we need to survive, so it has been theorized that epigenetic mechanisms evolved to stop transposons from moving around the genome. Furthermore, since transposons can rapidly alter DNA sequences, they are thought to play a major role in the processes of evolution and speciation (how a species evolves into a new form). In plants, transposons become highly active in response to stressful conditions, and this could act as a rapid source of short-term mutation when the environment starts pressuring you to survive or die. In addition, an animal’s genome changes when they are domesticated (like going from a wolf to a dog, or from an aurochs to a cow), and a majority of these changes occur in transposon sequences. No one is really sure why or how this happens, but it is clear that viruses play a very important role in rapid genetic change.

Abiological virus (whether it is a true virus, an endogenous retrovirus, or a transposon) can literally lay dormant in a word document as a string of As, Ts, Cs, and Gs. In other words, viruses can exist independently of genetics, solely in the symbolic dimension of evolution. A virus is nothing more than an idea until it finds a host within which it can replicate itself. Despite their ephemerality, viral sequences are clearly important for our lives as humans. After all, they compose nearly half of our genome and seem to play an important role in our long-term evolution.

In many ways, viruses are eerily reminiscent of the idea of ancient spells, which sit quietly as words in a book until someone utters the mystical syllables and unleashes the magic contained within. Perhaps due to the mysticism of this concept, many scientists and philosophers have a hard time accepting viruses as living things. But, whether or not you classify viruses as living entities, they certainly show us that the line between living things and pure information is a lot fuzzier than we often think…

Adapted from the book Organumics: An Epigenetic Re-Framing of Consciousness, Life, and Evolution by Ben L. Callif

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