Slashdot Mirror
Prions Evolve Despite Having No DNA
An anonymous reader writes "Scientists from the Scripps Research Institute have shown for the first time that 'lifeless' organic substances with no genetic material — prions similar to those believed responsible for Mad Cow disease and similar, rare conditions in humans — are capable of evolving just like higher forms of life. The discovery could reshape the definition of life and have revolutionary impacts on how certain diseases are treated."
until there is a flame war about whether this proves the existence of God or not?
Where's your God now?
Genetic material and DNA aren't really synonymous, are they? Alien life that appeared independently of that on Earth would likely have "genetic material" that served a similar purpose to DNA, but wasn't DNA.
Prions are proteins that, like viruses, replicate via a host cell. All the high-level principles of evolution by natural selection apply; it's just the low-level mechanisms that are quite different.
http://c.myspace.com/Groups/00017/98/88/17938889_l.gif
That must be how the Crystalline Entity came into being.
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
Are Rebublicans technically life-forms?
Natural selection doesn't pre-suppose DNA. Anything which multiplies to produce copies of itself, which can degrade/mutate between generations can evolve just in exactly the same way. Selection pressures work exactly the same. So does the chain reaction effect of multiplication of the survivors, resulting in major shifts in characteristics of a population.
But the actual story is the bad news part of it. That using anti-prion medication probably won't work all the time as it would just breed a drug-resistant breed of prions by preference.
Definitely bad news. We can forget about having the "saviour" take a bath in the daily oatmeal for our protection :)
Quidquid latine dictum sit, altum videtur
Less than a minute?
Shrug.
Computer memory is just fancy paper, CPUs just fancy pens with fancy erasers; the 'net is just a fancy backyard fence.
It's time we recognized that the interesting things about "life" are all just products of the fact that all kinds of systems can convey self-replicating entities of some sort, and they tend to be interesting and undergo evolutionary processes and etc. Whether they are non-biological DNA bundles, cellular organisms, oddly folded proteins, crystalized clay, etc.
So where are the nefarious / useful engineered prions at?
Evolution can be loosely defined as "change over time." Everything in our Universe is evolved under this definition, the key is time. The constants of our Universe provide the selection pressure and the matter provides the instance.
Shh.
Don't get me wrong, dna has some neat copying-related properties... but evolution is not about dna. The idea came along long before the physical basis of human heredity was understood, and it is a far more general principle. To get evolution via natural selection, all you really need is: ... that is heritable ( prions, dna, epigenetic markers, and cultural practices all have this to some extent or another)
1. Variation
2.
3. and something that ensures differential survival (as simple as limited resources).
These aren't very hard criteria to fulfill. The sticking point is really the heritability bit, but once prions work out the "how to propagate more of me" problem, evolution comes along for the ride.
Even from a purely materialist perspective, it seems reasonable to ponder a class of materials that replicate themselves. How exactly they do so might be more or less complex but the basic idea that it's possible to configure matter in a way that it replicates itself doesn't seem that absurd. And there's no particular reason it has to be DNA --- there are even purely mechanical possibilities.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
I don't think this discovery will mean anything about the definition of life. Rocks evolve too.
Evolution is not a capability of living beings, living things, inorganic things or whatever.
Evolution is the result of passing time, environment pressure and changes.
It's not the subject who evolves, it's the differences from 'starting' subject and 'surviving' subject what is called evolution.
Is this just another form of evolution or does it impact the very core of genetic evolution? I wonder how Richard Dawkins will react to this having based his life on the study and preachings of Charles Darwin's Natural Selection and genetic mutation/evolution. How does this affect those theories, is the evolutionary process as closely intertwined with DNA as first thought?
If I glanced correctly at this article, which does ramble on, prions are rogue proteins which aren't just detrimental to the organism, but cause other proteins to mutate as well. It wasn't clear to me if they do this by altering the genetic code or the neighbouring proteins directly.
The host organism may apparently have DNA of such nature that a random mutation reliably triggers the disease symptoms. This indicates to me that the code molecules exist in a higher energetic state and them getting upset makes them fall to a predictable lower energetic state which happens to produce malignant proteins.
This doesn't seem to be about wether or not prions are alive, but if disease is living. I think that instead of giving life a broader sense, we need to split the concept up to be more specific. I would be comfortable calling things that have neurons and therefre possess intelligence "living", and everything else "biomass". That way a tree isn't alive, but it is capable of becoming dead biomass. A person in a coma isn't alive, but enters the category of biomass.
Of course more useful definitons are possible. This is just something to tickle your creativity.
All rites reversed 2010
Not really related, but it is entirely possible for humans to be "alive" in a physical sense even after they are brain dead. As long as they are hooked up to respirators etc., they can be kept alive indefinitely. To date, no human being is ever known to have regained consciousness after brain death.
The _big_ catch here is that most physicians are not properly trained to test for brain death. Most physicians will just see a flat line on an EKG and declare the patient brain dead. I used to work at an organ transplant center, where there were technicians that went through a formal checklist to make sure the patient really is brain dead. It was not uncommon to find patients who did not meet the strict criteria. In the most dramatic example, a 3-yo boy was supposedly brain dead, and he was in the operating room, ready to have his organs removed. The technicians discovered that his pupils did respond to light, so they rushed him out of the OR. On the way back to his room, the boy opened his eyes and smiled. But then he went back into a coma and died 5 days later.
Needless to say, the boy's parents were furious.
Just a theory, you guys!
Lol, not really. I had to do that.
After all there's nothing "magical" about DNA. Any self replicating molecule should theoretically be capable of evolution if the replication process is less than perfect.
Seven puppies were harmed during the making of this post.
it's late, i'm over tired and maybe i should have cooked that last brain i ate. anyway i did a reread of Darwin's TOOS and then binged on a buncha evolutionary theory and evo-devo stuff, this over the last 3 years. 1st off evolution theory, at least the mainstream stuff presupposes a genotype (dna) translated into a phenotype like me typing this. so the question should arise as to whether prions have a genotype source that has a transcription mechanism. old school Darwinianism as penned by Darwin drifted toward acquired characteristics a la Lamarck because Darwin didn't have any working knowledge of genetics even tho Mendel had sent him a draft of his work. somewhere over 95% of all species have gone extinct and after all the reading and questions i came away seeing life as a random walk of living crud crusting eons of dead crud. no winners no losers no game no gameplan just stuff that hasn't died yet on top of stuff that has; being slow cooked by a middle aged average sun.
ideopath @ play
*insert joke about prion overlords here*
I didn't know technicians could declare death.
This explains how someone with a rock for a brain could evolve. His is a prion version of V.
I'm not quite sure I would call it evolution. I can easily imagine that many prions replicate not only themselves but variations as well and those variations will produce variations of different proportions and so on and so forth. So just because you subjected a prion to an adverse environment for a particular copy of a prion only means that form will be less populous.
It feels to me that this is less evolution and something more akin to chemical computation. Although ironically it does in some ways remind me of the poorly labeled Conway's game of life.
Any matter has one mission and one mission only: to find greater order. If matter without DNA or any prior form of order couldn't achieve more order, then life would not exist. Things want to be able to interact with their environment more efficiently, and must evolve to do so.
For what it's worth, everything can "evolve" - ranging from a speck of cosmic dust all the way to a galaxy - depending on how something is measured determines life by the definition of that measure. We and everything else are all part of that same continuum - more precisely, where do we draw the line at not drawing a line?
I thought at some point, the definition become
"Non-random survival of randomly mutating replicators"
How is this not a surprise then?
As posts above testify, the word "evolution" is used more and more in contexts that have nothing to do with life.
For example people talk a lot about the evolution of ideas, societies, and so on... Quite possibly, the philosopher Wilson is one of the popularizers of this approach.
Anyway, this also leads to a different point - Evolution by itself is not a proof of the existence of Life. For example, Ideas or Societies are not living organisms, yet they do evolve.
So the fact that prions evolve does not mean they are alive! One can fairly say that they are just a chemical (a protein) that can reproduce itself, evolve, and do damage.
In Science, Mathematics and Philosophy, it is very common to take "edge cases" in order to better understand the limits of an idea. Prions give us a good example of something that can reproduce and evolve, yet its a chemical not a living organism.
So what is "Life" ? Perhaps we should require the ability to perceive - awareness of ones surroundings - in order to define true life? In that case Bacteria aren't alive either, which is fine by me.
Jellyfish and Lizards do qualify as alive. More generally, you would need some sort of functioning nervous system (however primitive) to be "alive". Brain-dead people would possibly not be "alive" by this definition.
All evolution is is random mutations, and the ones best suiting to survival ... surviving. Or in this case, continuing to exist. Dust particles in space can be said to evolve, the ones closest together might one day form a star. There's nothing new here, if weird organic matter happens to be more resistant to anything trying to destroy it, then we might define it as evolving.
A (bio)mass, fighting for resources.
(If you raise the point, that that would include remote-controlled robots: Well yes, we control them, like limbs. And we live.)
Any sufficiently advanced intelligence is indistinguishable from stupidity.
The same thing is happening to biology what already happened to Newtonian physics with relativity theory.
Ceterum censeo Microsoft esse delendam.
that but not by much. Basically they'll say little changes like that (they call it micro-evolution) can happen but nope, no big ones into other species. (But anybody that's taken Bio 102 and seen how impossible it is to come up with a definitive answer to what is one species is and what is another knows that differential is horse-shit.) Guess they needed that so they could have an excuse why it was ok to take newer antibiotics and such. (You know, so they could allow the evolution that's so obvious you have to be pretty much insane to say it doesn't happen.)
Did you know 80 to 90% of the moderators on slashdot wouldn't recognize a troll even if one dragged them under a bridge.
From the Article:
The researchers began to see new prion-infected cells after leaving the swa-sensitive prion in the drug for 22 cell divisions, which took about 22 days. In other petri dishes, drug resistant strains did not emerge until the cells had doubled over 50 times, or for 50 days. From these results, Weissmann's team approximated that one swa-resistant prion will emerge for every one million new prions that are formed.
Does that mean that all individual prions in all petri dishes were successful in spreading?
Prions scare the living brain out of me.
Possible maybe, but likely? There is probably a reason that DNA (and RNA) are DNA and RNA and not something else. It's the same reason by complex chemicals/life chemicals are mostly constructed around Carbon. Carbon has lots of free valences, which allow it to act like a universal lego-block. Other elements, just don't have as much flexibility. It's why it's entirely unlikely that you will ever see something that can be classified as life that isn't carbon-based. Other elements just can't be as flexible as Carbon.
Over-the-top Response Guy! Giving "Over-the-Top Responses" since 1970.
Seriously, you do realize that HIV is a virus, NOT a genetic disorder?
Over-the-top Response Guy! Giving "Over-the-Top Responses" since 1970.
...and I then remembered the year I spent on a Federal work release program and the nasty bathrooms in the facility housing. Those bathrooms had plenty of DNA.
Just because some prions are different than others, and those differences cause them to last longer, linger around longer, etc does not mean that they are evolving. It's not as if the prion wakes up one day and says "I'm going to change". The suckier prions just don't make the cut. There's a difference.
I want to delete my account but Slashdot doesn't allow it.
Not new. See
http://en.wikipedia.org/wiki/Manfred_Eigen
"In addition, Eigen's name is linked with the theory of the chemical hypercycle, the cyclic linkage of reaction cycles as an explanation for the self organization of prebiotic systems, which he described with Peter Schuster in 1979."
Evolution doesn't require DNA, and the theory is like 40 years old at least.
How'd those housing starts go in November? Oh, down 19%?
8 years of republican rule drow the country to horrible depression and debt. Yes, democrats haven't been able to stop that in a year. Whooppedoo. Whether democrats have done good or bad decisions is nearly irrelevant here. There hasn't been enough time that their policies (especially long-term ones) could even theoretically have reflected to financial sector that much.
There is no way you can blame the current economic situation as a whole on democrats.
How are the continuing job loses going? Oh, another 200,000 jobs lost?
Same thing here.
How's that withdrawal from Iraq going?
I'm with you here. The government should certainly have progressed much faster in getting rid of Bush-era mess. They really haven't done well there. Even so, you can't blame the Iraq (or Afghanistan) mess on current government.
Nice to see our DHS Secretary telling us all how well the system worked when a jihadi got on a plane with a bomb.
And wasn't able to cause any damage... Yeah, it is true that current government should have removed all those unnecessary and inefficient post-911 security stuff from the airports. They (and their voters) should be ashamed that this hasn't happened yet. Even so, you should have hard time blaming democrats on those, either.
I hear Gitmo is going to be closed any decade now.
And just wait until you see the asshattery unleashed when Khalid Sheikh Mohammad et al are tried in a standard criminal court.
This is getting old at this point. "Republicans did something horrible when they were in charge. Democrats haven't cleared all the mess yet. Ergo, democrats are horrible."
Nice to see we have a Democratic Senate Majority Leader who thinks it's great that the President is "light-skinned and doesn't speak with a Negro dialect".
No fucking wonder Senator Harry Reid (D-Nev) is polling about 30 points behind his probably election opponent.
...
I'm not even answering to this one.
Think you can come up with a health care "reform" that relies even more on bribery and political payoffs and pisses even more people off?
How about forcing people to buy health insurance even if they don't want it? Where are all the libertarians-of-convenience who got so up in arms over the freedoms lost when a relatively small number of phone calls to known Al Qaeda related phones where intercepted without warrants? Where are all those JACKASSES when Democrats propose laws that would literally unconstitutionally under penalty of jail time force millions of people into private contracts that they don't want and cost thousands of dollars a year?
Private contracts? Well, at least the original drafts included government supported options.
That said... Yeah. The current plan for health care reform is horrible abomination. Not a single country with socialized medicine does it like that. It has the downsides of both systems. They really should ditch it.
Democrats. TOO DUMB TO KNOW THEY'RE DUMB
Aside from that last point about health care reform, your whole post was a collection "Republicans have messed up so througly that democrats haven't fixed those things yet" points. I certainly would think of democrats as the lesser evil based on that.
Any system that can self replicate can evolve. Period.
If there's a difference, your post didn't explain the difference. In fact, your post seems to suggest you don't have the foggiest idea what evolution is. I know looking skeptical can be cool, but it's only cool if you start from a position of knowledge on a topic. Otherwise, you just look stupid.
The world's burning. Moped Jesus spotted on I50. Details at 11.
I read the article and here's my educated opinion (with quotes and everything):
"In the classic sense, prions, which are misfolded versions of the brain protein PrP, cannot mutate because they do not contain DNA or RNA. They can, however, give rise to variants with different properties, possibly due to differences in the folding, or shape, of the proteins."
We can observe these mutations first hand. I drive a Prion to work. (My coworkers like to tease me about my little car and call me the Prionic man).
"On the face of it, you have exactly the same process of mutation and adaptive change in prions as you see in viruses," said Dr. Charles Weissmann in a prepared statement. Weissmann, who is the head of the Scripps Florida Department of Infectology in Jupiter, Fla., led the study.
Despite having colonized Jupiter, there are still many surprises left in scientific research but with each surprise comes the realization that everything is the same.
"Based on the number of times the cells divided and the number of prion-positive cells in the dish, the group could roughly estimate how quickly prions became swa-resistant."
In other words, we must drench the planet in swa before the prions have a chance to resist.
"In other petri dishes, drug resistant strains did not emerge until the cells had doubled over 50 times, or for 50 days."
Intensive scientific humor has shown to cause this mutation. The barrage would have to last longer than the biblical rains that flooded the earth.
"The fact that new prion "substrains" can appear and spread among cells in just a couple dozen cell divisions suggests that drug-resistance could easily develop in the lifetime of the host, from mouse to man."
It can 50 days whether in mouse-years or man-years, it matters not.
It's not like DNA appeared ex nihilo. Doesn't seem too much of a stretch to apply evolutionary biology outside of DNA now, does it?
Sometimes they occur in the organic chemical domain using DNA. Other times not.
Same invariant properties apply:
1) Self-replicators take resources from their environment in order to self replicate.
2) Mistakes sometimes happen in self replication. Sometimes they enhance replication. Usually not.
Salt crystals in solution, YouTube videos, DNA, Money, Religion. It's all pretty much the same, structurally.
Is this being taught in universities yet, or have they not caught up?
Please do not read this sig. Thank you.
Does this mean my stagnant Folding queue could be out of date?
In "Energy Flow In Biology" Harold Morowitz posits that an open system between an energy source and an energy sink, containing such elements as can form a variety of bonds and forms, will absorb energy, and form compounds that will persist in that state for a time in inverse proportion to how much energy is required to maintain the state. Increasingly complex forms can be created from those simpler forms if they persist long enough. Those more complex forms can have variations in their subunits locations and forms relative to the components from which it is built. This is the first chapter. The rest of the book is a bit of physics and a great deal of physical chemistry showing why the proportions of organics found on Earth as inevitable given the conditions of the Earth's environment and the combination of elements from which is is made.
The evolution part applies to the first chapter though. Some compounds self-catalyze, producing more. Some catalysts form that produce other products, but only do so when the first of those products form. Variations such as radicals appearing in different places on a benzene ring produce different forms, and catalysis can cause this to happen step by step, forcing the radical to 'march' around the ring.
Increasing complexity, with variations in forms of those increasingly complex forms, each of which have more or less ability to contribute to furthering these phenomena, that pretty much describes what life does. Maintaining itself at a level of complexity above the environment (read that 'maintaining itself in a state of negentropy) for a time, using the incoming energy, described something much like how life appears in contrast to its environment.
Again, this is all based on physical and organic chemistry, pre-biology. It's only logical to expect the activities of living things to mirror the activities of their non-living constituents. No, those compounds are not alive, but if they couldn't do those things, neither could life.
A marker then for life might be detection of compounds that carry out some functions we see in life, and an environment that allows them to increase in amount and in complexity. Where then do we put the dividing line between life and non? If we can objectively define and predict an emergent property that appears at a certain point in the growing complexity of the chemical soup that is characterized by a behavior which is necessary for life but is absent in the pre-living material, we might be able to describe that sufficiently to say it's one definition of life.
If it hasn't occurred to you before, it should now: a different environment and collection of compounds might also produce organics (or the equivalent based on other elements) will produce different results. If life, that will be different. Taking the definition from one situation is hobbling yourself when it comes to discovering other forms of life. It might also occur to you that there is no time scales associated with any of this. If we then take the broader view and don't limit 'life' to the result, but include it in the components, we can at least start with a statement about a component being 'alive enough to consider that aspect'.
We need as broad a view as possible so we will be able to recognize it when we see it elsewhere. A part of science is dedicated to looking for it. With our present definitions, which should be stated "Earth-like life" rather than simple "life", we are primed to not detect any forms of it which we could imagine but which differ significantly from Earth forms.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
http://xkcd.com/520/
anyone else read this as:
"prisons evolve despite having no DNA"?
I didn't understand how they could be surprised that prions evolve, so I checked with the original article. They weren't. They were interested in the rates of evolution and the persistence of strains that were selected against. Quite reasonable.
Even totally inorganic matter evolves, in a rough sense. At it's basis evolution just asserts that those forms which are most suited to an environment tend to persist in that environment. This seems quite hard to challenge. Then it accepts Malthus computations on population, and asks: Given that it's obvious that not all descendants can survive, what does the two laws in combination imply?
N.B.: Darwin didn't know ANYTHING about DNA. Genetics hadn't yet been recognized. (This was after Mendel, but long before he was discovered.) So the basis of evolution clearly CAN'T depend on those facts. Evolution is really quite simple, it's just the working out of the details that is complex. (Just as Boolean logic is quite simple, but it's a long and complex way from Boole to a compiled program written in C.)
I think we've pushed this "anyone can grow up to be president" thing too far.
Ok I accept without problem that you can have cellular evolution, ofcourse you dont need DNA, there can be different mechanisms that we are not aware of.
My interest is in these prions, they are organisms, they are living, but they do not have DNA !
I was always interested to know if there were other forms of life not based on DNA occuring in nature. This would imply to me that there is more than one tree of life, there is the tree of life that is based on DNA.
If life can for readily if conditions are acceptable, (like on earth) why would there be only ONE tree of life, and why is it not possible for there to be new trees formed by other chemical reactions but not DNA.
So is that what we have here, living cells, or organisms that are NOT based on DNA, and I ask is that another seperate tree of life, with it's own evolutionary path ?
Business practices, military strategies, popular music, whatever -- _everything_ is forced to either evolve and adapt to the environment as it changes (whatever environment that may be) or die out.
I'd recommend you relax, son. Freedom of speech means we get to say things you don't like.
also, you're a dick.
they react to things, they grow, they die and give birth to more ideas/ societies
look up the word "meme"
in fact, much as biological entities are nothing more than the vessels in which living, changing, competing genes exist, our minds are nothing but units in a game of living, changing, competing memes. language is the unit of information exchange
in fact, genetic change in humanity has ceased to be important. genetic change, across all species, now takes a backseat to memetic change in terms of evolutionary importance. evolutionary importance in this context meaning: the potential to extend life into new realms
we won't get off earth because of genetic change. we will get off earth because of memetic change. we are the dead end result of genetic change, and we became that when we evolved language and writing. with that leap, we closed the book on genetic change as being of paramount importance in terms of life's potential and opened a new book and a new era in life. we are in the beginning of a new era of memetic change, wherever that may lead, with or without us
genetics and genetic evolution just isn't the biggest most important game for life anymore. we're the interface between that and the new memetic era of life
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Depositing infected semen into the rectum was the cause of a huge percentage of cases when the disease first came to light. Just pointing that out, not making a value judgment on unprotected anal sex. Obviously that's less of a problem now that people know about it.
I'd recommend you relax, son. Freedom of speech means we get to say things you don't like.
also, you're a dick.
Yeah you better believe it, I'm also right :)
Offtopic.
Signature test.
Virginia is for lovers. EVE is for griefers.