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Prions, Darwin's Friend
blamanj writes "Prions, the recently discovered bits of protein thought to be responsible for mad cow disease are turning up all over. It has been shown that prions change the behavior of yeasts, and may therefore offer a speedy way for yeast to evolve."
infectious.
I, for one, welcome our new super-evolved yeast overlords.
Super beer! Man, for once all this science mumbojumbo actually pays off!
=Smidge=
Does this mean that it's no longer safe to drink beer and eat bread?
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
If only the Selfish Protein knew how much pain it's causing mankind.
Somebody call Dawkins. I smell another book.
Instead of relying on technology all the time, maybe we could get back to actually living for working instead of working for a living.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
Great. Just what we needed. Smart Bread (Except during Passover)
-- If you try to fail and succeed, which have you done? - Uli's moose
Yeast, LOAF...
Taco, what are you trying to tell us exactly?
Karma: Chameleon (mostly due to the fact that you come and go).
...from DNA methylation effecting cell differentiation and cloning and cancer to this new possible epigenetic mechanism for coping with environmental stresses. It doesn't live in the DNA sequence it lives in the runtime. How much more really cool stuff will be found that may be driven by the DNA or the puzzle pieces may be sequenced by it, but doesn't exist "on paper."
This wouldn't be the first time they "discovered" that something that is "bad" in some cases is "good" in others.
;)
So what does that article tell us?
That, by having a protein (infectious variant prion) that causes others to malfunction (generating altered proteins), so, in some cases, it *can* cause a "spontaneous" (read:accidental) mutation/selection that will (in the short run) allow that cell to survive when it normally wouldn't have, thus creating a evolutionary "short-cut".
Wellcome to the "Darwin's Evolutionary Theory", advanced applied random methods of selection.
In other words: wellcome to 100 years ago.
Duuh
By reading this signature you agree to not disagree with the post you just read.
I consider technology to be a natural extension of evolution - it's just that the progress is not totally random, so it's a lot more effective.
This is interesting for a number of reasons, but the one that sticks out in my mind is the transfer of plasmids between prokaryotes. Eukaryotes, like eyu and me, don't pass our DNA around as casually as, say, Staphlococcus Aureus does. This has the benefit that our DNA is relatively stable, meaning that we are almost guaranteed to be able to breed with someone two or three generations younger than we are ourselves (hellOOOO, Hef!) but the trade-off is that we're not very responsive to environmental stressors that require quick adaptation to survive.
In simpler terms, through conjugation live bacteria can pick up spare DNA from other living bacteria and immediately "evolve" to meet a new environmental challenge without needing to wait for another generation to be born before the mutation can take effect. The plasmid DNA is then passed along to the daughter cells of successuful bacteria. This obviously confers huge selective advantages on bacteria which pick up plasmids that code for antibiotic resistance genes.
I interpret this prion research in yeast to suggest that yeast can experience the same kind of variable protein expression as bacteria, throught the mechanism of prion inactivation. This is significant because eukaryotic cells do not experience conjugation, and generally do not have plasmids, but DO transport various small proteins across the cell wall and into the cytoplasm.
And if it works for yeast, perhaps the prion mechanism is intended to perform the same function in humans, or in the cows that end up with BSE. The test would be to find some gene in a higher mammal that expresses one way when a prion is in conformation A, but expresses another way in conformation B...
Humpty Dumpty was pushed.
Be patient, Grasshopper.
well, human gene base is quite small compared to animals i recall, something like two chimps from the same tribe can have more variation in the genes than two humans chosen randomly from anywhere from the planet.
(though, there's differences in average height and whatever, i guess that would count as evolution that those change between distant generations)
world was created 5 seconds before this post as it is.
I've done extensive experiments with thousands upon thousands of mad cows. It seems those nasty prions actually do some good; the cows in bizarro land had much higher rates of survival!
Heinlein's Methuselah's Children talked about genetically improving humans. Unfortunately, unimproved humans found the "improved" human too revolting to deal with.
Star Trek: TOS touched on human evolution with Khan's supermen, as well as with the two personnel (the commander(lieutenant?) and the psychologist) who got zapped by an ion storm.
Isaac Asimov touched on it in his universe with the Spacers. (Specifically one of the first fifty or so worlds colonized from Earth...that one developed a race of humans with telekinetic power.)
The overall fictional consensus seems to be to not directly force humans to evolve, but to let things happen as they do. The vast majority of humans are intolerant of overt differences from the norm. And the "superior" breed will get a superiority complex that really causes a clash.
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It's neat to see that prions are involved in inheretance. We inherent only DNA from our fathers, but there are lots of cell parts that don't come from nuclear DNA, but divide from our mother's egg. Not to mention that our genes can be "active" or "inactive" when we get them.
BTW, could you please consider using capital letters? Your comments are getting better (less flamebait), but it still drives me nuts that you aren't willing to take the time to press a shift key now and then. I'm sorry that this is as nice as I can ask, I'm not as perfect as I'd like to be.
'SBEMAIL!' is better than a goat!!
It was so bad, that from looking at mitochondrial DNA it looks like we are all descend from a one woman.
_Every_ animal and plant species trivially descends from one individual (counted as females from mitochondrial DNA for simplicity, but it holds for the "real" DNA as well). Nothing strange about it.
What makes our recent past interesting is that the youngest common ancestor is a lot younger than the species. That can indicate a population crunch - though it is not proof of it by any means.
A speciation event would look just the same, for instance - a separate subgroup splits off and grows to dominate, while the original species dies off. Of course, nobody would see it as a speciation event until enough time has passed for the distinct groups to actually differ enough to no longer be able to interbreed.
Trust the Computer. The Computer is your friend.
The problem with the SFnal vision of the "hated race of supermen" (which goes at least back to Slan) is that no one is going to breed a race of posthumans who are superior to their makers in every way, nor is one going to emerge by mutation. Instead, if it does turn out that substantial improvements to the human germline are possible, what will happen is that we'll tinker around the edges, improving things here and there. The improvements that will make up the change from human to superhuman will happen one at a time, and be perceivable as a Big Change only from a historical perspective. No one at the time said, "we're in the middle of the Renaissance," or, "Here comes the Industrial Revolution."
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
As an Israelly, I would say one needs smart bread especially on Passover.
I can see the adds now: "your merchandise will evade religious/government inspectors by itself ! A fortune saved in bribes !"
Working for necessity's mother.
It's one thing to assert evolution through unknown mechanisms (as Darwin did), and another to identify and model these mechanisms.
If this is true, and if this is widespread (at least in prokaryotes), than this may be a significant addition to the understanding of epigenetics's role in evolution. Very much NOT 19th century.
( Disclaimer: IANAB )
Working for necessity's mother.
human gene base is quite small compared to animals
"compared to other animals".
If "safe" prions could be harnessed or even engineered and a human could be placed in an environment that would stress their inbuilt abilities - eg space travel, it must be possible to pass on the "benefits" of their MACRO evolution to the next generation - perhpas getting rid of legs or whatever else would suit long term space dwellers.
Imagine a ship travelling to our nearest neigbouring star, it would take several generations for us to reach there so the colonists when they arrived wouldn't actually be "human" like we are!
Now if we can work out the environment on the alien planet before we send off the ship, we could engineer the prion/environment to force evolution's hand to create the modifications required to live in the environment they're going to.
I feel a novel coming on!
In this light, the mechanism of yeast prion action is more akin to some error prone repair and replication mechanisms in bacteria, which are triggered by stress and result in an increase in spontaneous mutations. This is different from plasmid transfer, which is a directed transfer of well-defined genetic information
In case of mammalian prions, I see no indication of a similar mechanism. Human prion protein huPrP is a cell surface protein which does not interfere with the translation apparatus or with genetic processes in the nucleus. It rather appears to be involved in regulatory processes which transduce signals from outside into the cell.
Yeast and mammalian prions share no common characteristics except for the ability to exist in to different conformations and to autocatalytically propagate one of these conformations. In general, prions are no functionally homogenous group. Another example would be the prions of slime molds, which play a role in the exchange of genetic information by cell fusion. Here the prion-conversion mechanism creates some kind of incompatibility groups, shutting down the fusion zone if two cells belonging to different compatibility groups try to fuse.
The prion phenomenon is a basic biophysical characteristic, it has not to be bound to a certain function. The fact that yeasts and fungi have found a way to use this physical property of certain proteins does not implicate that other prions have to have useful functions also. It is absolutely possible that mammalian prions are a purely pathological phenomenon.
This comment does not exist.
Noah's wife?
Or, yeah yeah, I've missed something
Or the cartoon ExoSquad, as I recall. That cartoon had a lot of promise. I don't remember if I ever saw the whole thing, but it was pretty grown up for a cartoon.
In this case, prions are causing the yeast cells to make slightly varied proteins. when they are exposed to stress conditions, some very very few of these infected yeasts gain a more efficient way of survival because of this pre-adaptation, thus by having the upper hand in the competition for limited resources, they are selected for survival. this effect is very similar to any kind of mutagens (mutation causing agents), in fact the main test to determine the potential of a chemical to cause cancer is working with a similar principle. so, to sum it up, they found out that prions can enhance mutation rate (not sure about this, is it really a permanent mutation which is inheritable or an error of post translational mechanism?) of yeasts. so, I don't see a big revolutionary discovery, just a novel discovery of an evolutionary mechanism.
You have a strange meaning for "recent"...
Reason is the Path to God - Anon
Timecube boy? Is that you?
The problem with that is that the Bible clearly traces three bloodlines through Noah's flood. Genesis describes one race as "the ancestors of all who now live in tents and who keep herds." Noah was not from that bloodline. Also, Goliath's race is mentioned both before and after the flood. Needless to say, Noah was not a giant.
Prions, Darwin's Friend. No they aren't. Darwin doesn't have any FRIENDS!
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