8% of Your DNA Comes From a Virus

An anonymous reader writes "About 8 percent of human genetic material comes from a virus and not from our ancestors, according to an article by University of Texas at Arlington biology professor Cédric Feschotte, published in the Jan. 7, 2010 issue of Nature magazine."

Comments

Not Bad

[pilsner.urquell]

Eight percent, I consider that a fair return on an investment.

Re:Not Bad

[je ne sais quoi]

Unless of course it's the 8% that makes you bald as you get older, or makes you susceptible to heart disease or diabetes, or any number of inherited undesirables. Remember, things like sickle cell anemia originated as a defense against malaria. In fact, in TFA it actually suggests an hypothesis:

"These data yield a testable hypothesis for the alleged, but still controversial, causative association of BDV infection with schizophrenia and mood disorders," Feschotte said.

where BDV here is the virus whose DNA they were searching for in the human genome. There you go, if you're depressed, manic or schizophrenic, it could be one of your ancestors got a brain virus.

Re:Not Bad

[digitalunity]

Unless it occurred recently and you're an intermediary state between mutation occurring and the mutation dying out.

Our modern civilization though protects the well being of even those with negative traits who would have otherwise naturally died out. That's not to say evolution in humans has stopped. Instead, we're simply not weeding out the negative traits.

Useful?

[Kolie]

Is any of that DNA in use or are those parts dormant? What effect do these modifications have on us beyond the initial use of replication and further propagation of viruses?

Re:Useful?

[Wonko the Sane]

Back with this story first came out I remember reading that DNA introduced by virus is thought to have given us the genes that allow the formation of placenta, which gave rise to mammals.

All the articles from around that time seem to be locked away behind paywalls now.

Re:Useful?

[tomhudson]

The weird thing is that research is now showing that a lot of the so-called "junk dna" is actually used indirectly. Maybe we like junk food so much because we eat what we are? :-)

But this whole thing isn't all that surprising when you consider where our mitochondria came from.

Re:Useful?

[Anonymous Coward]

"The viral DNA that isn't conducive to death probably stayed in." -- There, fixed that for you.

Re:Useful?

[vadim_t]

How would they know?

Hero of Alexandria didn't have trains in mind when he made his Aeolipile. It was used as a fancy way to open temple doors. Only much later people figured out a practical use for it.

Boolean algebra was a very obscure branch nobody cared about until it suddenly became very useful.

Lasers, IIRC didn't have an immediate application when they were invented. They definitely didn't have DVD drives in mind.

Re:Useful?

[icegreentea]

Apparently a lot of the ERVs (that 8% of our DNA made from retrovirus pieces) get expressed during pregnancy by the fetus. One of the results is that the mother's immune system gets depressed (apparently a lot of HIV-like stuff going on there) that prevents the mother's immune system from killing the fetus. There's probably lots of other fun stuff going on that we don't know about yet. It's actually really cool when you think about it... mammalian childbirth being possible because some immunodepressent virus infected some reptile a long long time ago.

Re:Useful?

[corbettw]

I am a pretty smart guy who doesn't understand the utility of pure research.

One of these things is not like the other, one of these things just doesn't belong!

Re:Useful?

[timeOday]

The viral DNA that isn't conducive to life would have evolved out

Evolution is a very noisy process. It does not assure that we are all maximally fit, only fit enough that all our ancestors managed to reproduce. The boundary of viability is people who are viable, but whose children are not.

Viral DNA might be introduced to our genome as a side-effect of viral infection at a faster rate than natural selection can remove it out of our genome, even if it is harmful to us.

And any benefit from schitzophrenia would have to be so significant as to outweigh the cost of losing touch with reality, which is enormous. Perhaps our DNA code for a randomized process that usually results in a healthy amount of creativity, but sometimes too much. That gene could be preserved even if it is deleterious in outliers. In fact the variability of gene expression ensures that genes advantageous in their mean effect are sometimes less advantageous, i.e. relatively harmful.

Re:Useful?

[Bengie]

I remember reading an article about sheep and virii. Some type of sheep use to have a virus that use to be bad for it. Even though this virus was bad, it did have one good attribute. It reduced the chance of a miscarriage and did it better than another "native" gene.

It so happened that this viral infection reduced the chances of miscarriages enough that at some point the virus stopped being bad for the sheep and they had a better chance to reproduce.

Now days, if you neutralize the virus, the sheep will always miscarry since the old gene got silenced/removed in favor for the virus.

The sheep and virus evolved to live together.

I read this a LONG time ago, i think it was in Discovery mag or something, but I can't remember much more than the idea of the story. The details might be slightly off, but the summary is the same. And they did talk as if the virus was still actually living in the host, not just select genes.

Re:Useful?

[Chris Burke]

In fact, back when lasers were first invented, people referred to them as "a solution looking for a problem". They were so cool, but for a while nobody could think of anything useful to do with them.

Silly folks.

"Insufficient awesome" is the problem, and lasers are the answer.

Like my PC

[Krneki]

8% of my Windows code comes from Viruses.

Bible Code?

[Gotung]

Isn't this "discovery" sort of like the Bible Code? So they searched the human genome and found a bunch of "virus like" patterns. Any sufficiently large set of information is going to give you some matches on just about anything you search for.

Re:Bible Code?

[FlyingBishop]

If you found a scroll in a cave that contained the book of John, would you say that it came from a different source than the book of John in the Bible? That's entirely different from rearranging letters until it says what you want it to say.

Re:Bible Code?

[SharpFang]

Not necessarily.
A virus infects a human. It gets to infect the sperm or egg cell. Insignificant part of genetic code gets replaced.
A child is born with -all- its cells containing the virus-originated code.

Of course the replaced part will be several genes at most, but if the mutation is insignificant or positive, it will remain in all the offspring. Meanwhile this may repeat any number of times and will be perpetuated through ages.

If a defect of lacking one whole chromosome is non-lethal (Down's syndrome), a minor damage to your genome has a really good chance of not affecting your offspring at all.

Re:Bible Code?

[2short]

"Any sufficiently large set of information is going to give you some matches on just about anything you search for."

Yes, but not a sufficiently large rate of matches. If the researchers are competent, they can calculate what percent of the data would be expected to match their search even if the data is just random, and decide if the match rate exceeds that by a significant margin. The 'researchers' of the Bible Code were clearly not competent in exactly this way.

As opposed to the paperback book market, Nature does not tend to print whatever comes across it's desk.

Re:Bible Code?

[Jhon]

If I found a really big scroll in a cave that contained billions and billions of apparently random letters -- but somewhere in the middle of all that was the text of the book of John (or "The Three Little Pigs" or whatever), I MIGHT suspect it came from a different source, yes.

Infinite monkeys pounding on keyboards over an infinite span of time would create the combined works of William Shakespeare, and all that...

Certainly not saying that's what happened here -- but the GPs question/point isn't entirely without merit.

Re:Bible Code?

[cmiller173]

Actually Down Syndrome (technically Trisomy 21) is having a whole extra copy of chromosome 21 not the lack of one.

Re:Bible Code?

[lyml]

There are 4^3000 (about 1.5*10^1806) different 3000 letter works (if you only have 4 characters). The odds of finding your specific one in a 3 trillion collection of random letters is so small, you can't even imagine how small it is. (approx 1 in 2*10^1794)

But let's try anyway. Imagine playing the universal lottery. You are supposed to pick one subatomic particle in the entire universe, and if you choose the correct one you get 1 nickle, the odds of winning is about 1 in 10^80, if you were to enter that lottery a billion trillion times a second (10^21) by the time all protons in the universe would have decayed the likelyhood that you would have won even once would be so small that you could not even imagine. Never the less.

Now imagine playing that lottery one time for each billion trillion times times you look through a different set of random characters (with each set being 3 trillion characters). After having won that lottery, not once, but enough times to build a tower of your nickles 1000 times longer than the circumference of the entire universe the likelyhood of you having found a matching set to your 3000 character set would be so close to 0, that you still can not even imagine how small it is.

So my guess would be that this virus dna didn't just appear by chance in the dna of humans.

Not surprising, given how DNA actually works

[IronDragon]

This is a fairly good little video that explains how RNA monomers end up naturally forming into longer polymer chains. Roughly 95% of our DNA is basically crap that only exists because at some point in the past, it was better at copying itself.

http://www.youtube.com/watch?v=U6QYDdgP9eg

Re:Not surprising, given how DNA actually works

[Gotung]

Actually I'm pretty sure 100% of our DNA is basically crap that only exists because at some point in the past it was better at copying itself ;)

Summary and article misleading

[Anonymous Coward]

These are endogenous virus fragments. Which means that a virus inserted itself into your ancestor's DNA. So you didn't get this new DNA after you were born, you inherited the 8% viral DNA from your ancestors.

Re:Summary and article misleading

[IronDragon]

Much like someone who copies the content of their old computer straight over to a new computer every few years. Repeat this process a few billion times, and you'll be quite surprised at the amount of sheer useless crap that just keeps getting copied. Voila! DNA.

But I use antivirus!!!!

[master_p]

Doesn't Norton protect me from such stuff?

Re:But I use antivirus!!!!

[Krneki]

It does, but as a side effect you are unresponsive 80% of your time.

Revelation

[schmidt349]

I'd like to share a revelation that I've had during my time here, Mr. Malda. It came to me when I tried to classify your species and I realized that you're not actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with the surrounding environment but you humans do not. You move to an area and you multiply and multiply until every natural resource is consumed and the only way you can survive is to spread to another area. There is another organism on this planet that follows the same pattern. Do you know what it is? A virus. Human beings are a disease, a cancer of this planet. You are a plague and we are the cure.

Re:Revelation

[ElectricTurtle]

To be pedantic, the difference between humans and animals is usually called reason, but in fact it's probably more specific if less poetic to call it 'problem solving'. Animals don't 'live in equilibrium' per se because that implies that they know what they're doing, as though they're thinking 'oh... I'll eat exactly this much and no more because that will mess things up!' Pfff I'll bet somewhere there's some green whackjobs who think that's exactly the romantic notion going through the brains of animals. (In fact, there are predators that kill even after they are full, just to kill. I remember watching a documentary about sea turtles and watching them hatch and try to make their way to the sea, and predatory birds were attacking them, first to eat them, but even after that they just kept killing and leaving the dead baby turtles there to rot.) Anyway, I'm rambling, point is, animals expand as far as they can. They consume as much as they can, whenever and where-ever they can, and reproduce as often as possible. What determines their numbers ultimately are things like the rate at which their consumed resources replenish and the rate at which they otherwise die from predation/disease/accidents/age, not some kind of instinctive population control.

So the contrast is, an animal, insofar as it thinks, thinks 'I will eat x' and then when x is scarce it thinks 'oh shit there isn't enough x!' Then depending on luck, it dies. Whereas humans think 'I like to eat x' and when x becomes scarce humans think 'well, this sucks, there isn't enough x anymore. Maybe I can eat something else? How about this? Ew. No, not that. How about this other thing? Meh, it's ok. Maybe I can cook it? What things could I do, or do in concert with others, that might restore the natural abundancy of x and/or allow x to be produced in an environment I control?' Yeah. That's why human population keeps growing, moving, adapting, and animals just have to suck it up. They can't solve resource problems creatively.

(Viruses aren't creative either, they and other micro-organisms just have such fast life cycles that it allows them to find mutations that positively affect their survival at a higher rate. In other words they adapt quickly by chance, humans adapt quickly by decisions.

Poor Summary

[Dr. Eggman]

The real news here doesn't appear to be that endogenization has occured through our past (OK, maybe the 8% number is news; I don't know about the numbers...) but instead that a virus, bornavirus, is displaying this property. This is news because bornaviruses are not retroviruses (previously the only know virus-types to produce endogenous copies.) Furthermore, the article seems to suspect that this virus may have ties to the schizophrenia and mood disorders...

Mammals

[Anonymous Coward]

Google for placenta and endogenous (as in endogenous virus). The placenta uses a lot of viral code, to the extent that it might be more virus than anything else. It also sheds a lot of viruses. The placenta is almost a different life form.

BTW, the Wikipedia entry shows that the "8%" number was known as long as 6 years ago.http://en.wikipedia.org/wiki/Endogenous_retrovirus

Re:Mammals

[MightyMartian]

ERVs have been known about for some time and are, in fact, one of the "killer" evidences for evolution. You can actually trace lineages with these genes, and they are useful for dating the splits between related lineages. For instance, chimps and humans share more ERVs than, say, humans and baboons. It's difficult to support that observation via Creationism, unless you proclaim the insipid "that's the way God wants it", but evolution explains it very neatly.

Re:Mammals

[canajin56]

"That's the way God wanted it" isn't the only way to support the observation of genes existing in multiple species, in a way that seems to imply inheritance. How about "God made life using OO programming"? Why would he start from scratch for every species, instead of just using copy & paste? If you really think about it...hacked together in 6 days, spaghetti code where 80% seems to be junk that doesn't even do anything, and is incredibly hard to decipher...God made us in PERL! Perl supports multiple inheritance, which explains the appearance of "viruses" transplanting genes from one species to another, unrelated species!

the OA refed in the OP link is in N&V section

[mapkinase]

http://www.nature.com/nature/journal/v463/n7277/full/463039a.html

That section is mostly commissioned and if not submissions reviewed by editor (technically, not peer reviewed).

The author of the referred N&V article is the author one of the articles in the reference section...

For peer-reviewed article, I would go for:

http://www.nature.com/nature/journal/v463/n7277/full/nature08695.html

written by bunch of Japanese:

Endogenous non-retroviral RNA virus elements in mammalian genomes

Retroviruses are the only group of viruses known to have left a fossil record, in the form of endogenous proviruses, and approximately 8% of the human genome is made up of these elements1, 2. Although many other viruses, including non-retroviral RNA viruses, are known to generate DNA forms of their own genomes during replication3, 4, 5, none has been found as DNA in the germline of animals. Bornaviruses, a genus of non-segmented, negative-sense RNA virus, are unique among RNA viruses in that they establish persistent infection in the cell nucleus6, 7, 8. Here we show that elements homologous to the nucleoprotein (N) gene of bornavirus exist in the genomes of several mammalian species, including humans, non-human primates, rodents and elephants. These sequences have been designated endogenous Borna-like N (EBLN) elements. Some of the primate EBLNs contain an intact open reading frame (ORF) and are expressed as mRNA. Phylogenetic analyses showed that EBLNs seem to have been generated by different insertional events in each specific animal family. Furthermore, the EBLN of a ground squirrel was formed by a recent integration event, whereas those in primates must have been formed more than 40 million years ago. We also show that the N mRNA of a current mammalian bornavirus, Borna disease virus (BDV), can form EBLN-like elements in the genomes of persistently infected cultured cells. Our results provide the first evidence for endogenization of non-retroviral virus-derived elements in mammalian genomes and give novel insights not only into generation of endogenous elements, but also into a role of bornavirus as a source of genetic novelty in its host.

Damn it.

[UncHellMatt]

She told me she was TESTED!

Re:Ob. Matrix quote

[causality]

Humans are a virus!

Before the Matrix, there was Bill Hicks: "I'm tired of this back-slapping 'isn't humanity neat' bullshit. We're a virus with shoes, okay?"

Re:Ob. Matrix quote

[ShieldW0lf]

The moral of the story is, cannibalism really does allow you to take your enemies strength. That's why we eat Jesus' flesh on Sundays, so we can absorb his holy virus and become like God.

Re:Ob. Matrix quote

[Anonymous Coward]

That's why I eat copious amounts of pasta, so that I, too, may be touched by His Noodly Appendage.

Re:Ob. Matrix quote

[jhoegl]

Ahhh religion, where changing flesh into bread and blood into wine isnt considered "witchcraft". Yet all other "magics" was at one time punishable.
Hypocrisy, it loves religion.

Re:What a crappy press release

[mcgrew]

No, 8% of your DNA comes from viruses that infected your anscestors' reproductive organs and were passed on to you. TFA is actually an interesting read.

A Woman's Perspective

[d34dluk3]

It's the Y Chromosome

Misleading title

[BurningRome]

The "8% of your genome" comes from the first paragraph of the News and Views article which reviews the actual article by Horie et al, and is referring to ALL viral remnants in the human genome, not just this new Bornavirus one. From a quick scan of the paper, it looks like they didn't estimate what fraction of the human genome comes from their Bornavirus, but they only describe 4 actual elements - so that's a vanishingly small part of the human genome. The vast majority of viral elements in the genome come from retroviruses and other retrotransposons, and that's been known for a long time.

Re:Ob. Matrix quote

[spun]

Commit yourself daily to serving The Lord

With some fava beans and a nice Chianti, fthfthfthfth.

Re:Ob. Matrix quote

[nedlohs]

How is that hypocrisy?

Raising the dead, walking on water, healing the sick, etc, etc. All can be done* by God as a miracle or by demons as witchcraft. It's not hypocrisy, it's caring about the source more than the action.

Having another religion is usually punishable, again not hypocrisy just standard religion.

* According to believers, a set I'm not a member of so I really should stop talking about their business...

Re:Ob. Matrix quote

[biryokumaru]

Turning people into newts.

Hey, he got better.

Re:Ob. Matrix quote

[flitty]

Wat? Transubstantiation is official church Doctrine for over 1/6th of the earth's population, and has been since The Council of Trent in 1551. I know it's simplistic to say that 1 billion people in the church all believe this teaching exactly, but come on, we're not talking about some strange, obscure cult here...

Re:Ob. Matrix quote

[AmberBlackCat]

Ahhh religion, where changing flesh into bread and blood into wine isnt considered "witchcraft". Yet all other "magics" was at one time punishable. Hypocrisy, it loves religion.

And Slashdot, where every story about biology turns into an attack on Christianity or some other faith. Things were different in the Pit & the Pendulum days, but lately it seems like you attack them way more than they attack you.

8 Percent!

[bitphr3ak]

I think I'll call in sick!

Re:Ob. Matrix quote

[Bobb Sledd]

You know, there's a real easy way to tell: If when the source is raising the dead, if you hear beautiful and calming and serene music in a major chord mode, then it is good. If you hear banging on a piano or dissonant violins, then evil.

Re:Ob. Matrix quote

[BobMcD]

The ability for a free human to decide what he does or does not believe is about as far from 'unimportant' as one can possibly get.

You can be insensitive to it if you wish, but this is a thin excuse at best.

Re:Ob. Matrix quote

[pluther]

Yes, because there's no real difference between pulling people out of their homes and torturing them to death and making fun of people's ignorance in an online forum.

Re:Ob. Matrix quote

[Opportunist]

Speak for yourself, I can hear God talking all the time in my head.

If only he finally realized I don't understand ancient hebrew...

Re:Ob. Matrix quote

[BitZtream]

No, atheists don't 'demand' anything really. Atheists are generally pretty normal people, just like most people who are religious are normal.

Nutjobs, who also happen to be atheists demand retarded shit just like religous nutjobs, they tend to be more 'scientific nutjobs'. And by that I mean that they seem to worship something they call science instead of religion, yet blindly ignore scientific method in favor of blindly believing what some guy wrote in a book/journal/website.

Same nut jobs, different books, same ignorance, and as you are so quick to show us ... the same name calling and he said she said.

Perhaps before calling someone a 'shitnut freak' for 'ranting against ' a religious group, you should consider not 'ranting against a(ll) religious group(s). Its cool though, you've obviously got plenty of angst to work out, you go on being mad at everyone in the world ... nutjob.