A new branch in the Tree of Life

February 17, 2006 3:57 PM

A monstrous discoverysuggests that viruses, long regarded as lowly evolutionary latecomers, may have been the precursors of all life on Earth. "We haven't even begun to scratch the surface. The numbers are mind-boggling. If you put every virus particle on Earth together in a row, they would form a line 10 million light-years long. People, even most biologists, don't have a clue. The general public thinks genetic diversity is us and birds and plants and animals and that viruses are just HIV and the flu. But most of the genetic material on this planet is viruses. No question about it. They and their ability to interact with organisms and move genetic material around are the major players in driving speciation, in determining how organisms even become what they are."
posted by five fresh fish (60 comments total)

You can see this sucker under visible light microscopy, it has more genes than some bacteria, and some of those genes do stuff no other known virus does. Yet virus it is.

The new virus, officially known as Mimivirus (because it mimics a bacterium), is a creature "so bizarre," as The London Telegraph described it, "and unlike anything else seen by scientists . . . that . . . it could qualify for a new domain in the tree of life." Indeed, Mimivirus is so much more genetically complex than all previously known viruses, not to mention a number of bacteria, that it seems to call for a dramatic redrawing of the tree of life.
posted by five fresh fish at 3:59 PM on February 17, 2006

"We haven't even begun to scratch the surface. The numbers are mind-boggling. If you put every virus particle on Earth together in a row, they would form a line 10 million light-years long. People, even most biologists, don't have a clue. The general public thinks genetic diversity is us and birds and plants and animals and that viruses are just HIV and the flu. But most of the genetic material on this planet is viruses. No question about it. They and their ability to interact with organisms and move genetic material around are the major players in driving speciation, in determining how organisms even become what they are."

Now, what surprises me is that biosciences have assumed viruses were flotsam fallen from the tree of life: bits and pieces of life, tossed out and happening to survive albeit via a sketchy bit of trickery.

Me, I've been assuming for years that viruses are the root of life. You can't get much more basic than a self-replicating chemical (and there are a few). Viruses seem the next step up from that, bacteria a bit more advanced, and cellular life the most evolved yet.

I guess naïve ignorance is sometimes ahead of the curve!
posted by five fresh fish at 4:04 PM on February 17, 2006

That's a really interesting article. Thanks, fff.
posted by 327.ca at 4:05 PM on February 17, 2006

And they will outlive us all, no doubt! :)
posted by LouReedsSon at 4:07 PM on February 17, 2006

The general public thinks genetic diversity is us and birds and plants and animals and that viruses are just HIV and the flu.

What kind of public edumacashion system you's runnin' down there?
posted by slatternus at 4:09 PM on February 17, 2006

"I'm so sick of this ain't humanity neat bullshit. We're a virus with shoes, people. That's all we are." - Bill Hicks
posted by milquetoast at 4:09 PM on February 17, 2006

Anyone with a more-than-passing interest in "artificial life" studies or "genetic algorithms" wouldn't be surprised by this at all. In particular, the "arms race" between parasite and host is a stunning evolutionary motivator.
posted by Slothrup at 4:12 PM on February 17, 2006

I knew there was something odd about her.
posted by goatdog at 4:19 PM on February 17, 2006

fff: "...the most evolved yet..."

Sorry to be the symantic dork that points this out - but none of us...fishes, virii, mefites...are any more or less evolved. Evolution is a process, not a destination.
I feel like I should be singing this.
We're all evolviiiiing togetheeeer...

However, if we're going to have this discussion, we should get that clear from the start.

IANAS, but isn't it possible that viruses represents the greatest biodiversity found on earth simply because they are capable of adapting so much faster than any other 'creature'?

Virii pass through generations extremely quickly.

Wouldn't this create a drastically larger body of genetic diversity within that particular tree of life?

I'll take my answer off the air, thanks.
posted by Baby_Balrog at 4:23 PM on February 17, 2006

I can see how they're driving evolution, but how are they driving speciation?
posted by Faze at 4:33 PM on February 17, 2006

The new virus, officially known as Mimivirus (because it mimics a bacterium), is a creature "so bizarre," as The London Telegraph described it, "and unlike anything else seen by scientists . . . that . . . it could qualify for a new domain in the tree of life."

Bite me, paramecium!
posted by Smart Dalek at 4:41 PM on February 17, 2006

Bite me, paramecium!

Anyone else have a "Chip's Challenge" flashback just now?
posted by Gator at 4:50 PM on February 17, 2006

Fascinating stuff. I'm much more aware of viruses and parasites these days, thanks to recent MetaFilter links.

And I'm probably full of both of them.

going to take a long hot shower and scrub off all of my skin
posted by davejay at 4:51 PM on February 17, 2006

I can see how they're driving evolution, but how are they driving speciation?

Maybe by accidentally insinuating themselves into the genetic code of more complex organisms?
posted by slatternus at 4:52 PM on February 17, 2006

five fresh fish writes "Me, I've been assuming for years that viruses are the root of life. You can't get much more basic than a self-replicating chemical (and there are a few). Viruses seem the next step up from that..."

But there's the rub! Strictly speaking, viruses aren't "self-replicating": they need to hijack the replication mechanism of another organism. That's why they were assumed to be followers; they need other organisms in order to reproduce. It's a reasonable conclusion to draw.

These new discoveries suggest that viruses were at one point able to reproduce on their own, but it's a capacity that they lost somewhere along the way...
posted by mr_roboto at 4:57 PM on February 17, 2006

biosciences have assumed viruses were flotsam fallen from the tree of life

The part of "bioscience" with a brain hasn't made this assumption.
posted by shoos at 5:03 PM on February 17, 2006

"The numbers are mind-boggling."
I feel sick
posted by Cranberry at 5:13 PM on February 17, 2006

I thought viruses absolutely required cellular life to reproduce, and this is the reason they're frequently classified as not being alive. If they require cells to reproduce, then maybe something like a virus was the first form of life, but not a virus per say.
posted by Citizen Premier at 5:23 PM on February 17, 2006

Great story.
Thanks, fff.

It almost sounds like Carl Sagan: "Billions and billions of virii..."
posted by bru at 5:27 PM on February 17, 2006

These new discoveries suggest that viruses were at one point able to reproduce on their own, but it's a capacity that they lost somewhere along the way...

right, kinda like mitochondria.
posted by gaspode at 5:45 PM on February 17, 2006

I'm only a lay biologist, but I think the article, like many science articles written for laymen, oversensationalises a bit. The line

"The precise order in which the three domains of life evolved—whether, say, the eukaryotes emerged before or after the archaea and bacteria—is a much-debated subject."

overstates the case; as far as I know, there's virtually unanimous agreement that eukaryotes emerged after prokaryotes. The debate, as far as I recall, is whether prokaryea or archea emerged first. And the statement that

Moreover, certain signature Mimi genes, such as those that code for the production of the soccer-ball shape of its capsid (an outer protein coat common to all viruses), have been conserved in viruses that infect organisms from all three of the domains, particularly in eukaryotes. The implications of that finding are truly radical: that Mimi, or a Mimi-like ancestor, emerged prior to the three other domains and played a key role in inventing the very cells of which humans and all complex cellular life-forms are made.

is extremely disingenuous. If we already knew that some viruses in all three groups shared certain genes, we already knew that all three groups had a common ancestor. The discovery of those genes in Mimi doesn't mean that its closer to the ancestor; it just means that we've, not surprisingly, found another virus with those genes. In truth, its entirely possible that genetic analysis indicates that Mimi is closely related to the ancestor of all three; one way (I think), would be basically to show that Mimi has more in common with each of the three group individually than they have with each other. And maybe that's the kind of stuff the researchers found, and the article is just glossing over it. But the evidence that actually is cited for Mimi's ancestry isn't compelling to me.

In addition, the article glosses over the major inconvenient fact in the theory that viruses evolved first: every known virus depends on host cells for replication. That's practically the definition of what a virus is. As the article suggests, its within the realm of imagination that a DNA/protein package could replicate without cytoplasm, membranes etc, in, say, the primordial soup. But Mimi infects amoebas.
posted by gsteff at 5:45 PM on February 17, 2006

"These new discoveries suggest that viruses were at one point able to reproduce on their own, but it's a capacity that they lost somewhere along the way..."

Couldn't there be some still undiscovered viruses that can reproduce, out there in the Pacific somewhere. It sounds like scientists really haven't been looking untill recently.
posted by MetalDog at 5:50 PM on February 17, 2006

MetalDog writes "Couldn't there be some still undiscovered viruses that can reproduce, out there in the Pacific somewhere."

What would the fundamental difference between a bacterium and a self-replicating virus be? Protein coat vs. lipid bilayer membrane?
posted by mr_roboto at 5:55 PM on February 17, 2006

Sorry to be the symantic dork that points this out - but none of us...fishes, virii, mefites...are any more or less evolved. Evolution is a process, not a destination.

Sorry, my bad. I initially was going to use "complex," but wasn't sure that was truthful, and foolishly wimped out with "evolved."

No harm done, I hope. I hate to think I've contributed to the dumbing-down of our public!
posted by five fresh fish at 6:06 PM on February 17, 2006

Here are some pictures of Mimi
posted by obedo at 6:11 PM on February 17, 2006

IANAVirologist, but I think our current understanding of viruses is that they are a bunch of genetic material (DNA or RNA) enclosed in a protein shell without any of the normal cellular machinery that's required for the virus to replicate and reproduce itself.

I don't think you'd find a virus that, strictly speaking, replicates itself and is a little living critter out there. But it's probably not too hard to expect that there are virii that, in addition to the protein coat and genetic material, have accessory proteins that mimic some of the functions that we see in full-fledged cells.

Also, (without having looked at the references) I wonder if any of the genes that are in this huge virus could be the result of recombination of the host genes with the virus genome.
posted by scalespace at 6:17 PM on February 17, 2006

What would the fundamental difference between a bacterium and a self-replicating virus be? Protein coat vs. lipid bilayer membrane?

That's a huge distinction. Lipid bilayer membranes work because they've got water inside them. And there has to be enough volume inside to keep any big stuff, like balls of DNA, from brushing up against it and disrupting them (DNA's exterior, in particular, is very negatively charged, which would mess up the membrane). So the difference between a ball of DNA surrounded by protein and one surrounded by membrane is one that would take a ton of evolution to bridge, enough so that, in my opinion, there's no particular reason to expect that one evolved from the other.
posted by gsteff at 6:17 PM on February 17, 2006

Wow, great article. Still skeptical as to whether it will become accepted science, but that is what peer review is for. My first thought was that this is the foundation for Stephen Jay Gould's Modal Bacter.
posted by TedW at 7:14 PM on February 17, 2006

Gsteff said: ...the major inconvenient fact in the theory that viruses evolved first: every known virus depends on host cells for replication ... Mimi infects amoebas.

Wouldn't it be the other way around? No host, no virus: no amoeba, no Mimi.
posted by cenoxo at 7:42 PM on February 17, 2006

gsteff - would take a ton of evolution to bridge, enough so that, in my opinion, there's no particular reason to expect that one evolved from the other

But you don't think that current viruses (genetic material bound up in a protective protein(+) coating) may have come from a lipid (bi)layer bound collection of genetic material (and various proteins involved in replicating said genetic material), right?

One of the more popular (although not entirely canonical) notions are that viruses are escaped bits of genetic material from cellular organisms (that persist because cellular organisms end up making more copies of them, and more copies of those bits that make themselves easier to copy).
posted by PurplePorpoise at 7:45 PM on February 17, 2006

Wouldn't it be the other way around? No host, no virus: no amoeba, no Mimi.

I think that's what I was trying to say. Mimi came after amoebas (or its preferred host).


But you don't think that current viruses (genetic material bound up in a protective protein(+) coating) may have come from a lipid (bi)layer bound collection of genetic material (and various proteins involved in replicating said genetic material), right?

Right... if you don't think viruses were around from the beginning, that's kinda the only way they could have formed. I just wasn't thinking of that as "evolving from" ceullular organisms. Semantics.
posted by gsteff at 8:05 PM on February 17, 2006

Is the article about viruses in general, or just this huge one? Because I want to read about the huge one, but I'm already familiar with virus as path to gene transfer between species and whatnot.

When you get down to the nitty gritty of evolution, things are so complicated, at least when you compare it on a 'gene' or 'species' level, because some genes can actualy damage themselves, but produce more ofspring in certan situations.
posted by delmoi at 8:46 PM on February 17, 2006

Me, I've been assuming for years that viruses are the root of life. You can't get much more basic than a self-replicating chemical (and there are a few). Viruses seem the next step up from that, bacteria a bit more advanced, and cellular life the most evolved yet.

I guess naïve ignorance is sometimes ahead of the curve!

Well, at least a little naive. because bacteria are cellular. I think you meant 'multicellular'. But your most naive assumption is:

Now, what surprises me is that biosciences have assumed viruses were flotsam fallen from the tree of life: bits and pieces of life, tossed out and happening to survive albeit via a sketchy bit of trickery.

That "biosciences" have assumed anything like that. If that's what the article said then the article is wrong. Geez. Science articles in the popular press are almost always terrible. Someone took something interesting, this big ass virus, and used it as an opportunity to get all epistemological about things that are really just abstractions anyway. Science doesn't say one thing is better or more "evolved" then another thing at all.
posted by delmoi at 8:50 PM on February 17, 2006

These new discoveries suggest that viruses were at one point able to reproduce on their own, but it's a capacity that they lost somewhere along the way...

There may have been viruses like that, and there may still be viruses that can do that today, but to say that viruses "used" to be able to do that is just a nonsensical statement.
posted by delmoi at 8:53 PM on February 17, 2006

This may be a dumb question, but are viruses (virii) alive?
posted by rleamon at 9:14 PM on February 17, 2006

In addition, the article glosses over the major inconvenient fact in the theory that viruses evolved first: every known virus depends on host cells for replication. That's practically the definition of what a virus is.

Thats the crux of the issue. A "virus" is a human classification. No virus can live without a host cell, because then it's not a virus, by definition.

Some bored science writer decided to get all breathless about it.
posted by delmoi at 9:27 PM on February 17, 2006

What was going on in that primordal soup anyway? I thought some of the models for how long chains of material grew and reproduced replicated have a passing resemblence to viral action in a cell.

Precursor or postcurser to life as we know it, it seems either way we are making assumptions we can't fully support.
posted by pointilist at 11:29 PM on February 17, 2006

I was running the numbers. At 2 microns a virion (I don't know if this is average but a few are that size), at 1.6 billion microns to the mile, at 6 trillion miles to the light year, to have virions stretched out for 10 million light years you would have approximately 5 * 10^28 virions. I have no doubt that there are a lot on earth, but this seems high.
posted by dances_with_sneetches at 5:04 AM on February 18, 2006

This is absolutely fascinating -- thanks, fff!

Now the viruses appear to present a creation story of their own... With the discovery of Mimi, scientists are close to ascribing to viruses the last role that anyone would have conceived for them: that of life's prime mover.

Who would have thought we'd find God hiding inside an amoeba at the base of an industrial cooling tower?

In the beginning God created the heavens and the earth. And God was a bug-eyed, hexagonal smurf with a head of electrified hair; and God said: "Si, mi chiamano Mimi..."
posted by languagehat at 5:44 AM on February 18, 2006

And, of course, as most of have heard from Laurie Andersen or the sentence's original author, the late William Burroughs, Language is a virus.
posted by kozad at 9:20 AM on February 18, 2006

thx, obedo! Awesome photos!
posted by five fresh fish at 10:10 AM on February 18, 2006

“This may be a dumb question, but are viruses (virii) alive?”

I don’t know much about recent biology, but when I was in school, the general thought was that viruses (not virii) don’t really mesh well with our definition of “alive,” most notably that they aren’t cellular and cannot reproduce independently.

This article seems to suggest two things: 1) that viruses such as Mimi may have evolved from something more complex which may have been able to reproduce alone, and 2) given the similarity between Mimi and a cell nucleus, it is possible that eukaryotic life began when a Mimi-like virus infected a bacterium and just set up residence.

Considering these theories, and the genomic complexity of Mimi, I’d say viruses are a form of life.
posted by ijoshua at 10:18 AM on February 18, 2006

Really interesting. Nice post fff.
posted by bardic at 11:02 AM on February 18, 2006

Stimulating post and thread five fresh fish. Thank you.
Like you I've assumed for many years that viruses were the root or at the root of life. The impulse to replicate intrigues me. Any ideas you or anyone else here have about what would 'motivate' a virus to survive by replicating, either by itself or as a parasite? Or is there something inherent in the 'nature' of replicating to keep on doing the same thing?

Would memes be synaptic virii or are they more like 'thought genes'?

Thanks TedW for the wonderful Stephen Jay Gould link, he's a scientist hero of mine, always loved his lectures.
posted by nickyskye at 12:22 PM on February 19, 2006

Motivation? Why would that enter into the picture?

There are molecular structures that "self-replicate." They catalyse a reaction, causing the raw materials to organize themselves to create molecules identical to the original.

Prions are complex proteins. They are not alive in any conventional sense of the word: they're just great big molecules. They come in "left hand" and "right hand" varieties, in that they can coil one way or the other. The destructive prions, ie. BSE, are coiled backward to some of our key proteins. When our right-hand proteins come in contact with the destructive left-hand proteins, our good proteins are turned into destructive wrongly-coiled ones, and go off to do their own bit of destroying.

Viruses are not alive in our conventional senses, either. But they get inside living cells, hijack the DNA or RNA systems, and create copies of themselves. I don't think you could call it deliberate or motivational about it: it's just complex chemistry.

I, personally, think this motivationless "it's complex chemical interactions" model works all the way up the complexity chain. We're a big bag of electrochemical reactions...
posted by five fresh fish at 1:05 PM on February 19, 2006

I agree with some of the previous respondants in that anyone with a basic understanding of life would not be surprised by this information - sounds like a news filler to me. I think I've learned more from our meta-mecs than the article itself.
posted by joepunk at 1:48 PM on February 19, 2006

nickyskye: Like you I've assumed for many years that viruses were the root or at the root of life.

Well, I think it's a bit premature to make such a conclusion about all "viruses" given their sheer diversity. It's possible that some viruses are the root of all life. It is also possible that some viruses evolved as mechanisms for a form of pesudo-sexual exchange of genetic information (analogous to plasmids.) It's not such a huge step from a protein tube for the purpose of sharing plasmids, to a protein capsule for the purpose of sharing plasmids, to a bacteriophage virus that only contains information about how to make more bacteriophages.

And it's possible that other viruses are radically specialized bacterial parasites.

The problem is that "virus" as a taxonomic category doesn't appear to imply much in the way of a common relationship. So in this case, it's probably a mistake to assume a common origin.

Would memes be synaptic virii or are they more like 'thought genes'?

The meme is a horrible simile that ignores the fact that quantitative theories of genetic evolution rely on some basic assumptions about genes that probably don't apply to other forms of information.
posted by KirkJobSluder at 2:57 PM on February 19, 2006

What a nice surprise to see you replied five fresh fish and KirkJobSluder. Thank you both. Nothing like a good think about something which previously was on the perifery of the Unarticulated Vague Ideas part of my mind.

Wikipedia says of viruses : "Obligate intracellular parasites are organisms that cannot reproduce outside their host cell, they force or compel the host to do their bidding." The use of the word "bidding" implies some sort of volition or impulse of sorts. I don't know what 'volition' is on the cellular level because that concept of bidding normally implies sentience.

I used the word motivate because there seemed to be something Darwinian about the lives of some viruses, in their transmutation. I didn't know what word to use for the impulse to replicate, which seems to be an inherent capacity of viruses. Why would viruses reproduce or hijack DNA or RNA systems? What's in it for the viruses or is it some automatic thing rather than Darwinian? It seems you, fff, think it's an automatic chemical thing.

I suppose what the virus 'gets' out of the hijack is to 'live', to exist? Is that part of complex chemistry, a tendency of chemicals to replicate for no 'reason'? Would Darwinian natural selection relate to viruses?

I never had anyone to think this through with and so appreciate your input. Off I went Googling "virus transmutation" and came across a delightfully badly written but interesting essay about the fact (?) that viruses do not transmute. I'm still trying to make heads or tails of this sentence which seems to say that viruses have an "infectious factor" and that is what propels viruses to replicate? "Different acellular infectious factors except viruses exist - folded only from RNA "wiroidy", "wirusoidy" and protein prion."

I like Dawkin's meme concept , find it useful and think it is a good simile . What interests me in thinking about both viruses and memes is the dynamic of replication and what propels replication.
posted by nickyskye at 4:00 PM on February 19, 2006

"Unarticulated Vague Ideas" are where I do my best hunting. I can almost always bag a strange thought.

The essence of evolutionary theory is basic maths. There is nothing "impulsive" or "motivational" or "violate" about it, as far as I've ever figured. It's simply 1 organism + 1 successful copy = 2wice as likely to continue into the future.

As far as I know, the DNA/RNA replication processes are wholly chemical in nature. A viral protein (?) that can succeed in hijacking that system, so that it makes copies of the virus instead of copies of whatever it was supposed to make, is a viral protein that will have a better chance of replicating itself in the future.

History utterly forgets the losers. If the catalyst 'plugs up' with waste materials, if the prion never bumps into its mirror-image good protein, if the virus enters a cell that destroys it, if a cell fails to thrive in its environment, if the last surviving dodo fails to find a mate... well, the patterns that made them what they were will no longer be influencial in the future.

In my opinion, the entire process is mechanically mathematical. There are no ulterior motivations, it is not 'guided' by an exterior influence, there is no intelligence behind it.
posted by five fresh fish at 5:15 PM on February 19, 2006

now, if you wish to explore the semi-articulate vague ideas, i have a theory that the universe consists of a pure-energy realm, the matter realm, and a consciousness realm. energy + consciousness => matter. the less probabilistic and the less entropic the matter, the greater the amount of consciousness involved in its existence.

but i assure you, this is pure looney speculation verging on religious, and there is nothing scientific and provable about it!
posted by five fresh fish at 5:18 PM on February 19, 2006

What fun! How nice of you to explore semi-articulated vague ideas with me. :) Just my cup of synaptic meandering, even if I didn't spell periphery correctly, lol. Like you I do not think there is guidance by an exterior influence, nor intelligence behind evolution but the nature of evolution seems to be intelligent, in that surviving seems intelligent. I guess I'm biased because I like surviving, lol.

Yes, those organisms that do not replicate successfully - or survive against the obstacles of living- disappear.

Why would something, like a virus, replicate? What is the urge to replicate? What propels it forward? Or is it down to the tautology, that which survives survives? That is something I don't understand. Intuitively the impetus to replicate doesn't feel mechanical or mathematical to me but, of course, there are scientific truths that are counter-intuitive.

Your theory of existence/consciousness sounds to me something like the concepts of Advaita Vedanta, as described in Surendranath Dasgupta's History of Indian Philosophy. Maybe consciousness and energy are connected in the way that Nicola Tesla thought about, in terms of resonance?
posted by nickyskye at 7:11 PM on February 19, 2006

nifty
posted by Smedleyman at 6:14 AM on February 20, 2006

IMO, those questions sound a whole lot like "why does a bike move forward? why does water run downhill?"

Why does a ferrocyanide-iodate-sulphite create self-replicating islands of reaction? The answer is entirely electro-chemical; there's nothing biological about it.

What is DNA? A chemical chain that operates rather mechanically.

How do prions and viroids replicate? By insinuating their DNA/RNA molecules into a cell's replication machinery.

None of these things seems particularly self-aware, intelligent, or otherwise magical. Up to this point it all looks pretty mechanical.

Ever seen an ice crystal form on the inside of a very cold window? You can see the water film self-organizing itself into the crystalline form as the crystal grows across the water. It forms patterns, it grows faster where the water is thinner, it works its way around obstacles and contaniments... and it is not alive.

I'm not convinced chemical self-replication, crystal formation, prionic and viroid diseases, and viral diseases are anything close to being alive. IMO they are mechanical operations and, as such, wholly predictable when we are fully informed of all variables.
posted by five fresh fish at 8:44 AM on February 20, 2006

...5 * 10^28 virions. I have no doubt that there are a lot on earth, but this seems high.

I did some back-of-the-envelope calculations, and that actually seems like a reasonable number. Consider: the human population of the world is about 6x10⁹. A human body is estimated to contain 10¹⁴ cells, so we're talking 6x10²³ cells in the world in living humans alone.

Humans constitute about 0.33% of the earth's biomass, so if the world's entire biomass were eukaryotic cells, you'd be talking on the order of 2x10²⁶ cells. But bacterial cells are smaller than eukaryotic cells--only 1/1000 the volume or so. Now things get a bit fuzzier, because I don't know what fraction of the earth's biomass is bacteria, but that could easily up the number of cells a few more orders of magnitude, so there's maybe 10²⁸ cells on earth. Of those, at any given time only a small fraction are infected by viruses, but those that are infected can have thousands of viral particles in them. So 5x10²⁸ virions seems a reasonable number to me.
posted by DevilsAdvocate at 9:48 AM on February 20, 2006

hmm, fff, good stuff to think about. :)
May I ask what you think is the difference between being alive and 'mechanical', bio-chemical replication?

I didn't mean to say in any way that I think viruses are self aware, intelligent or magical, lol, nor to use the word intelligent in any way related to the controversy about "intelligent design". I meant to question the dynamic of replication, trying to comprehend what propels it forward, rather than ending. You seem to be confident in your understanding about the mechanical-chemical nature of replication. Thank you for sharing the interesting info about self-replicating ferrocyanide-iodate-sulphite.

It would seem that replication is enabled by the laws of physics. My curiosity is about the nature of replication itself and for example, what propels viruses to hijack the DNA and RNA, replicating as a kind of parasite.
posted by nickyskye at 10:23 AM on February 20, 2006

nickyskye: I like Dawkin's meme concept , find it useful and think it is a good simile . What interests me in thinking about both viruses and memes is the dynamic of replication and what propels replication.

The devil of course is in the details. Memetics goes beyond just saying that genes are a good simile for ideas, and claims that the very rich and precise theories of quantitative genetics can be applied to the communication of ideas.

However, quantitative genetics is based on some non-trivial properties of genes that don't apply to chunks of information that are recreated every time they are used and modified to fit context.
posted by KirkJobSluder at 12:02 PM on February 20, 2006

I guess I take a functional view of things, at least at that level of complexity: viruses do what they do because that is what a thing built like a virus does.

I think it's inevitable that we will engineer viruses just as mechanically as we engineer swiss watches. I don't think we are manufacturing life at that point. We are making a mechanical gadget — a tourbillon, in a way¹.

In my mind, asking "why does a virus replicate" is like asking "why does a tourbillon keep time?" "What motivates a tourbillon?" "What does a tourbillon want?"

And in other lines of thought: perhaps life is at the point beyond which we can predictably and reliably design it from scratch.

This has the disturbing implication that for a complex enough understanding of probability, one might not view an individual human as alive, but merely the highest probability of a constrained set of predicted results.

¹ The tourbillon: a beautiful and bogglingly complex bit of tiny engineering. Wonderful!
posted by five fresh fish at 12:10 PM on February 20, 2006

KirkJobSluder, I get the impression you think the term meme is sloppy, unscientific, inaccurate thinking and that memes should not be related, even by simile, to the precisely scientific understanding of genes.

The comparison between memes and viruses has been discussed in Thought Contagion: How Belief Spreads Through Society by Aaron Lynch, a mathematician and philosopher who worked for many years as an engineering physicist at Fermilab.

In referring to Elizabeth Loftus' work about the changing nature of memory are you saying that you think genes are unchanging, rigidly fixed and do not adapt? It seems to me genetics are all about mutation, hybrids and change, much like memory.

There is a German saying, "jede vergleich hink", meaning every simile limps. Memes are not genes. However there is enough substance in the similarity to make meme a useful concept for some people, including myself.

fff, "viruses do what they do because that is what a thing built like a virus does". Yup, down to that tautology. Guess I need to do some more research, examine the various theories different scientists have about replication.

There is something non-mechanical to me about viruses, so it's hard for me to conceptually aliken them to a tourbillon.

"perhaps life is at the point beyond which we can predictably and reliably design it from scratch". Ooh, that's something to think about. Looks like that's another thing to research, what is the difference between what is alive and what isn't on the cellular level?

I don't think, like you do, about life as mechanical or that human beings are "merely the highest probability of a constrained set of predicted results."

But I do love the tourbillon! Thank you for the wonderful images of exquisite engineering that are beautiful, deliciously complex.
posted by nickyskye at 3:31 PM on February 20, 2006

"viruses do what they do because that is what a thing built like a virus does". Yup, down to that tautology.

Only because the question is, if you accept that DNA mechanisms are chemical, nonsensical. It's like questioning the motivations for a soap bubble to form a minimum-area surface. There are any number of mechanical reasons, and none philosophical.

I don't think, like you do...

I don't. At least, not with the least confidence.
posted by five fresh fish at 4:49 PM on February 20, 2006

nicky: think you'll like this.
posted by five fresh fish at 5:03 PM on February 21, 2006