Were Ancient Viruses a Key to Human Evolution?

When the mapping of the human genome was completed in 2003, researchers discovered a shocking fact: our bodies are littered with the shards of retroviruses, fragments of the chemical code from which all genetic material is made. This discovery has created a new discipline, paleovirology, which seeks to better understand the impact of modern diseases by studying the genetic history of ancient viruses.

 

 

Highly infectious viral diseases -including the Plague, yellow fever, measles, smallpox and he Spanish Flu, which killed 50 million people at the end of the First World War, moving from one cell to the next, transforming each new host into a factory that makes even more virus. In this way, one infected cell soon becomes billion -that die when the host dies.

Endogenous retroviruses, however, once they infect the DNA of a species they become part of that species:  they reside within each of us, carrying a record that goes back millions of years. Molecular battles of endogenous retroviruses that raged for thousands of generations, have been defeated by evolution.

These viral fragments are fossils that reside within each of us, carrying a record that goes back millions of years. Because they no longer seem to serve a purpose or cause harm, these remnants have often been referred to as “junk DNA.” Although many of these evolutionary relics still manage to generate proteins, scientists have never found one that functions properly in humans or that could make us sick.

That is until Thierry Heidmann who runs the laboratory at the Institut Gustave Roussy, on the southern edge of Paris,  brought one to life. Heidmann long suspected that if a retrovirus happens to infect a human sperm cell or egg, which is rare, and if that embryo survives—which is rarer still—the retrovirus could have the evolutionary power to influence humans as a species becoming part of the genetic blueprint, passed from mother to child, and from one generation to the next, much like a gene for eye color or asthma.

In a brilliant essay if The New Yorker, author Michael Specter brought Heidmann's discovery to life, showing how by "combining the tools of genomics, virology, and evolutionary biology, he and his colleagues took a virus that had been extinct for hundreds of thousands of years, figured out how the broken parts were originally aligned, and then pieced them together. After resurrecting the virus, the team placed it in human cells and found that their creation did indeed insert itself into the DNA of those cells. They also mixed the virus with cells taken from hamsters and cats. It quickly infected them all, offering the first evidence that the broken parts could once again be made infectious. The experiment could provide vital clues about how viruses like H.I.V. work. Inevitably, though, it also conjures images of Frankenstein’s monster and Jurassic Park."

Heidmann named the virus Phoenix, after the mythical bird that rises from the ashes, because he is convinced that this virus and others like it have much to tell about the origins and the evolution of humanity.

“This is something not to fear but to celebrate,’’ Heidmann told Specter one day as they sat in his office at the institute, which is dedicated to the treatment and eradication of cancer.“What is remarkable here, and unique, is the fact that endogenous retroviruses are two things at once: genes and viruses. And those viruses helped make us who we are today just as surely as other genes did. I am not certain that we would have survived as a species without them. The Phoenix virus sheds light on how H.I.V. operates, but, more than that, on how we operate, and how we evolved. Many people study other aspects of human evolution—how we came to walk, or the meaning of domesticated animals. But I would argue that equally important is the role of pathogens in shaping the way we are today. Look, for instance, at the process of pregnancy and birth.’’

Heidmann believes that without endogenous retroviruses mammals might never have developed a placenta, which protects the fetus and gives it time to mature, which eventually led to live birth, one of the hallmarks of human evolutionary success over birds, reptiles, and fish. Eggs cannot eliminate waste or draw the maternal nutrients required to develop the large brains that have made mammals so versatile. “These viruses made those changes possible. It is quite possible that, without them, human beings would still be laying eggs.”

Posted by Casey Kazan. New Yorker Article Link: Darwin's Surprise

Related Galaxy posts:

Don't miss the fascinating video,  The Ghost Map -the story of the great cholera outbreak that devastated London in the 1870's.

The Ghost Map
Deadly Companions: Animal-born Microbes Pose Threat of Global Pandemic
Hot Zone: Scientists Unlock Secret of 1918 "Spanish Flu" Pandemic
Pandemics from Outer Space Possible? Europe's Scientists Discuss The Future of Humans in Space

Comments

[Joku]

"Highly infectious viral diseases -including the Plague..."
As far other more wise people have concluded, plague was Yersinia pestis - a bacterium - not a virus.

[shutit]

nobody likes a know it all mate

[k b]

its entirely concievable that with science currently pursuing virii as a delivery system for drugs and nanotechnology, that some earlier group knew more about this and used it to 'engineer' a rapid evolution . after all, the common cold and aids are both retro viruses and able to drastically alter ones lifestyle and if aids can hijack and re program cells , theoretically, with the proper knowledge , how hard would it be to re engineer humanity on the fly so to speak

[Joku]

How about you shutting it?

So what if I am not liked because I point out a fault..? See if I care as I am health professional.
If I give out antibiotics for virus, I am just doing a mistake, and say that something serious is viral when it is bacterial and therefore most likely to be treatable, that is malpractice.

These articles are supposed to be based on science, therefore examples the writer uses should be accurate as well.

[shutit]

I'm just a troll trolling around don't mind me

[Liam]

I had hopes for this story but it was a crock'

[matt]

They should really stop medicating people with aids... It'd be way more humaine to let them die off than allow them to live long enough to infect the rest of us. People just dont think things through anymore.

[Cale Howe]

Am I the only one in the last year who has read this and cared to post that such experiments are quite literally walking on the edge as far as genetics goes?
Why are people so worried about cloning when this guy is resurrecting dead ancient virus's that have the ability to infect again? What if the cure for one of the viruses was a compound only produced in some extinct plant or animal. And in theory, couldn't he resurrect the oldest know virus, one that affected all mammals, or even possibly all life that derived from that single organism. Seems like the risk of stumbling on a life killing pathogen is kinda dangerous. One careless worker at the wrong time could destroy the world. Don't get me wrong I see how this is useful in doing basically the same thing to the viruses. Wouldn't this prove what didn't kill us made us stronger? I would be more at ease with this to know that you have some way of knowing the strain of virus you are reanimating before you actually do it. As such risks in my opinion shouldn't be taken unless there is reason for the risk. Is it possible to reverse engineer your process to instead allow the virus to die and see where it might fit onto our DNA? I mean if you can reanimate a dead virus that has become part of our DNA wouldn't that mean that the entire being of the virus should somewhere fit onto our DNA and effectively make us immune to that virus? Seems like a more safe and sensible way to utilize the knowledge? I'm sure you guys have thought of this by now though, and if you haven't please use what you already know now to attempt this. And please don't let anything you can't kill live for longer then 8 hours. I mean anyone handling such risk shouldn't be allowed to even touch it, let alone move it after tirelessly studying it. What I'm getting at is simple, figure out a way to study it without having to risk any form of accidental exposure. I mean this is really serious stuff here. I mean this is kinda the same as the military making bio-weapons. This man tells us not to be afraid of it's applications without even tell us what we should be afraid of. Imagine a virus that killed everyone who didn't have green eyes, or worse yet a virus that say was specific to one culture in one area at one given time somewhere in history and only they are immune to it. This is a bio-weapons gold mine, one that could give a country the ability to cause mass genocide without anyone ever knowing it.

[Huevos]

Ugh! It never ceases to amaze me how some of the smartest people on earth can also be damned idiots.

Bringing dead viruses of totally unknown danger level back to life should be a crime punishable by death. Any scientist who thinks doing something with a 1 in 50 million chance of causing devastation to humanitiy is ok, should be drummed out of his or her profession for wanton disregard for human life (and an utterly incompetant understanding of math)