Did Ancient Viruses Spur Human Evolution? A Galaxy Insight

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:

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

[Jason Bourne]

Wow that is truly amazing!

RT
www.privacy-center.pro.tc

[Dr K]

The Plague is not caused by a virus!
Interesting though.

[zanuda]

Awesome

[A conservative]

Are you attributing this quote to Thierry Heidmann?

"It is quite possible that, without them, human beings would still be laying eggs"

That is completely ridiculous. Think about it.

[Joe]

Bubonic Plague is bacterial. We strongly suspect, but cannot confirm, that the Black Death of the 14th and 15th centuries was the pneumatic form Bubonic Plague; however, there are flaws the bubonic plague theory and evidence which supports the idea that it was caused by a (now extinct or mutated) viral pathogen or possibly a combination of comorbid pathogens.

[Justine]

Very interesting but hard to take it seriously when there are so many grammatical errors. I'll have to read up on it.

[TAXICAT]

interesting, but poorly written =/

[musicaleCA]

This article cannot be taken to be factual. The author did not take the time to properly research the subject they are writing about. Claiming that the Plague was caused by a virus, when that claim cannot be substantiated with solid proof is a gross breach of a journalist's responsibility to report factual information accurately.

More accurate (and more recent) information can be found through NewScientist and various scientific journals.

[Bill]

Interesting, but definitely more information would be nice.

[Shelly]

Very good discussion! Pondering our origins and history is always good for our future.

[Brad]

somebody should tell them there doing it wrong...we're supposed to be getting rid of disease not bringing it back to life lol

[claudio]

Intelligence inherited and pervaded via a virus or retrovirus ??
Any comment would be possible to this theory.

Likely and NOT surely the Neanderthal was destroyed by a virus that our ancestors 'the sapiens' survived.

Was that virus that spurt intelligence in our ancestor of higher level than that of Neanderthal ??

What fantastics theories....a new moovie could be done.

New species of the 'Homo tree' supposedly appeared randomly here and there......no Contacts , no Viruses to be propagated...in those remote days...among these local branches of the 'Homo tree'...incomunicatable ...distant thousand of Km.

Then what a new theory invented ...and supported by what ??? Proof of concept ?? gemomas comparisons ???
Natural fantasy ??

Sorry ....seems rather strange this 'theory' without any support...any scientific base.

Good luck and regards to the virus that made us intelligent...or supposedly intelligent.

[Cody]

wait did human beings ever lay eggs? did anybody else catch that? i think this guy knows more about history than all of the world.

[dmtbilly420]

dude Zanuda..you're so correct, i noticed that too..what do they mean still laid eggs..there is only one inference that could be deduced following such a statement...humans or the previous being before evolving into humans, laid eggs..that's pretty ridiculous! check the credibility of this.

[mgl]

I could see this happening. I'm surprised that there is a name for it already and the name is Junk DNA.
That means it's been around for a long time and I'm just hearing about it, I guess.

[Jade]

Fascinating. The fact that they reconstructed an ancient buggy is pretty awesome on it's face. But I would like to see more connection to actual evolution of the animal as opposed to conjecture (which was all I saw in terms of actually effecting evolution) before the question becomes too evolutionarily significant.

[UncoocoxY]

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[SiliconJon]

LOL on the eggs comments. He's using a simplified example of the change, and I'm not a fan of oversimplification to the point of inaccurate representation for the sake of laymen understanding, as what's the point in getting a half-assed visual if you destroy the correct idea behind the issue in the process.

Maybe this is better: imagine if various life forms on earth did not develop this particular mechanism in defense against a virus, keeping all births to be egg-orientated, while the other mutation(s) that lead to human evolution still occurred, assuming they were significantly virus induced as well in order to keep to the theory that such evolutionary stimulus were to occur.

Is that better? :P