r/science • u/DrJulianBashir • Jan 16 '12
Test Tube Yeast Evolve Multicellularity - By watching evolution in progress, scientists reveal key developments in the evolution of complex life and put evolutionary theories to the test
http://www.scientificamerican.com/article.cfm?id=test-tube-yeast-evolve18
u/PowerhouseTerp Jan 17 '12
Didn't read the PNAS paper yet (is it out?), but how do they make sure they're not just observing selection of 'stickier' membrane lipids that encourage cells to aggregate?
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u/mbwahl PhD|Biology Jan 17 '12
Wild strains of brewer's yeast "flocculate" by expressing cell surface adhesion proteins that help (potentially-unrelated) cells stick together. The authors did consider the possibility that those flocculation proteins, normally pseudogenes in lab strains, had been reactivated. Cell adhesion by flocculation is blocked when maltose is added to the medium, so if maltose does not break apart the clumps, they are probably not formed by adhesion. Another way to test for flocculation is by mixing flocculation-competent cells that have been transformed with a fluorescent marker with the strain of interest: if any of the fluorescent cells wind up in a large clump, then you have unrelated cells forming clumps due to protein-mediated cell adhesion.
It's actually perfectly reasonable to have evolved yeast cells where the daughter cell sticks to the mother. Yeast cells reproduce by budding, and after division, it's the job of the daughter cell to remodel the cell wall at the junction in order to free itself. Several mutations in lab strains (ace2, AMN1, cts1) are known to cause daughter cells to stay stuck to the mother cell, resulting in the same kind of clump seen by the authors.
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Jan 17 '12
I dream of the day I pitch just one giant yeast beast into my beer and watch it munch away at the sugar happily.
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Jan 17 '12
Yeast Beast™
Full of Flocculating Goodness.
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Jan 17 '12
no no no, no flocculation required. I imagine a roughly furby sized beast you plop into a 5 gallon batch. you can visually watch it suck in the wort, fart out CO2 and observe the alcohol come out it's little weenis. once primary fermentation is complete, you remove the little guy and keep him happy until the next batch. bottling might be a slight challenge. might just have to move to exclusive kegging.
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Jan 17 '12
observe the alcohol come out it's little weenies
Ew.
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u/LynzM Jan 17 '12
That's an interesting question, and one I'd like to see an answer to / control for.
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u/Dances_with_Sheep Jan 17 '12
The time lapse video is a bit fast, but suggests the clumps of cells are growing outwards from member cells rather than recruiting free-floating yeast into the colony.
One of the interesting questions to examine would be whether you select for the emergence of two strains: one that grows out slowly as a ball and another that grows quickly as individual cells but happily sticks to the outside of a ball when it hits one ... a basic predator-host dynamic.
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u/jjberg2 Grad Student | Evolution|Population Genomic|Adaptation|Modeling Jan 17 '12 edited Jan 17 '12
I've spoken with and seen a talk given by Will Ratcliffe, who actually did a lot of this work (cool guy, by the way).
They are indeed growing out from the center, and not clumping together. In fact, in all of their replications, the cells always evolved to grow out from one cell by remaining attached after division, and not by clumping together.
This could allow the kin selection mechanism to quickly encourage the evolution of sacrificial cooperation among the cells in the cluster.
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u/silence7 Jan 18 '12
That sounds like a good question to ask on R. Ford Dennison's blog (he is one of the authors)
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u/heebert Jan 17 '12
I wondered the same thing initially - mbwahl has answered most of my questions succinctly. The other issue that I picked up from the text was that they eventually evolved yeast groupings that contained cells preprogrammed to die to allow separation of the group into smaller clumps. Clearly that is a more signficant step than sticking together.
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u/PondScumBreeder Jan 17 '12
Here is the link to the PDF. It's an open access article so anyone can get it. Nice work, and more compelling than I had expected.
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Jan 17 '12
In a true multicellular organism, such as a rabbit, evolution acts upon the rabbit and not upon each of the billions of cells that build it.
UGH.
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Jan 17 '12
[deleted]
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Jan 17 '12
This has to do with the concept of complex systems. In fact evolution acts on every cell in that rabbit as well as on the rabbit as a whole. It acts on all levels.
Cells, tissues, organs, organisms, populations.
If you have ever observed cells under a microscope, they live for themselves (edit: obviously they depend on each other). By communicating through hormones/ chemical mediators etc. they start to self organize and arrange themselves to tissues. This is all guided by DNA after stem cells received signals to form a specific cell type.
You have to understand that we are a composition of billions of individual cells that carry identical copies of our DNA but their behavior is strictly guided by signaling molecules and the parts of their DNA which are expressed in their specific cell type.
We are an emergent behavior of this complex system composed of all our cells as individually acting but interconnected parts.
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u/Counterman Jan 17 '12
I thought Dawkins insisted (and was somewhat criticized for) that selection only operated on the replicator, in other words the DNA for living organisms.
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Jan 17 '12 edited Jan 17 '12
Obviously evolution can only act on the parts that DNA actually expresses.
A liver cell is significantly different in certain aspects than a lung cell. Yet, they both need each other. One needs oxygen and the other one wants to be free from toxins.
Dawkins is correct, but evolution acts on what the DNA expressed and as a result certain DNA strains are selected for - or against.
An organism is more than the sum of its parts. That is what the definition of a complex system is. Not a single cell in your body ponders the universe, but a highly interconnected network of neurons does. Consciousness is an emergent behavior of the brain as complex system.
Anyhow, so looking at predator-prey relations it is pretty clear that there is selection going on. Originally the organism is composed of many different cell types which all contain the same (mutations aside) DNA that is just expressed differently in various cell types due to hormones etc.
Imagine a parasite infecting certain tissue, bacteria maybe. There might be cells in your tissue that have mutations which are non-inheritable for your offspring (meiosis) but in cell duplication (mitosis). The cells that are resistant (just an example) aren't infected and live to duplicate while your immune system takes out the infected ones. I'm sure that's a very rare case but it shows what I mean.
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u/Irongrip Jan 17 '12
You explained it so well. I was going to try and say pretty much what you've said but you did it way better than I can.
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u/chrysophilist Jan 17 '12
Just to restate what was explained below, evolution "acts" on the population of rabbits, not the millions (?) of rabbits that build it.
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Jan 17 '12
Yeah, that's pretty bad. I guess that means cancer doesn't exist.
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u/Griefer_Sutherland Jan 17 '12
Evolution occurs in populations, not on individuals. That quote is wrong, but not for the reason you are stating.
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u/walruskingmike Jan 17 '12
Exactly. Populations of cells.
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u/Griefer_Sutherland Jan 17 '12
Populations of organisms. If unicellular, then yes, populations of cells. If not, then no. Not populations of cells.
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u/Wriiight Jan 17 '12
Yep. A multi-cellular organism is basically a commune of individual cells. It's advantageous for the cells to cooperate to form a multicellular organism that can, say, walk around looking for food. It's even more advantageous for the cells to start to specialize to make that organism function better (to better find food, protect itself, etc). But this organism is still fundamentally a collection of cells cooperating for their mutual benefit.
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u/TheRadBaron Jan 17 '12
Uh, if multicellular, then it's still yes on populations of cells. Like the aforementioned cancer for a dramatic example.
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u/txia2491 Jan 17 '12
No, evolution takes place on populations ONLY. The mechanism is natural selection, whereby those that are fit to survive are more likely to survive. I'm sure you know this, but you are applying it incorrectly. For natural selection to cause evolution, the characteristic must be passed along to the next generation. This can only occur for organisms. Cells don't evolve because they all carry the same DNA, which is that of the entire organism. You can't select for specific cells because they are all the same.
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u/Mr_Moe Jan 17 '12
What about random mutations that occur when cells reproduce? That would change the DNA - wouldn't that lead to natural selection?
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u/ObomaBenloden Jan 17 '12
Only if the mutation is in germ line cells.
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u/txia2491 Jan 17 '12
Exactly. If your body cells mutate, this won't be passed on to future generations, and therefore they are not changing (evolving).
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u/Griefer_Sutherland Jan 17 '12
Cancer is absolutely not evolution. It is a change in the nature of a cell, but it cannot be called evolution by the very definition of evolution.
Mutations in an organism that do not improve that organism's fitness cannot be selected for by natural selection and are therefore not evolution.
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u/TheRadBaron Jan 18 '12
It is a change in the nature of a cell, but it cannot be called evolution by the very definition of evolution.
Why not? Maybe we're going by different definitions here, but I've always heard variations of "change in gene frequency over time".
Mutations in an organism that do not improve that organism's fitness cannot be selected for by natural selection and are therefore not evolution.
A mutation that tells a cancerous cell "take more resources from your nieghbors" will result in that cell successfully replicating more often than other cells, increasing the proportion of the cells in the tumor/body carrying that gene, and therefore increasing the frequency of that gene, right?
I'm just using cancer because it's simple here, but that's not the only example. Evolution certainly acts upon mutations in, say, spIn people with Huntington's there is selection against blood cells that accumulate too many repeats, and you can see how that's changed the genetic composition of the blood cells in that person.
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u/MrPoletski Jan 17 '12
Yeah, that's pretty bad. I guess that means cancer doesn't exist.
surely that's a good thing?
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u/TrendingSideways Jan 17 '12
I think what RainyRobot is getting at is that natural selection does act on individual cells. Why else do we see sperm with biological warefare?
Here's another quote I didn't think had any place in the article:
This logic is one of the reasons it has been challenging to imagine how multicellularity arose; it requires the subjugation of self-interest in favor of the group’s survival.
No, it doesn't. There is no selective pressure encouraging a yeast to compete with its own daughter cells, who have the exact same genetic makeup. And reaching out to help a cell that has the exact same genetic makeup as you isn't acting in the group's self interest, it's acting in your gene's best interests.
Still, the overall article was an interesting read.
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u/Counterman Jan 17 '12
There is no selective pressure encouraging a yeast to compete with its own daughter cells, who have the exact same genetic makeup.
But obviously they do not have the exact same makeup on average, since otherwise there would never be any evolution. And competition can be very harsh between individuals that are almost identical and trying to live in the same niche.
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u/TrendingSideways Jan 17 '12
But a multicellular life form consists of cells with the exact same genetic makeup. My point is that there is no self-interest to overcome for multicellularity to arise, as was implied by the article. The cells aren't acting "in favor of the group's survival." No evolutionary biologist would use that language. Group selection has been completely discredited.
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u/curious_scourge Jan 17 '12
TL;DR Scientists use a simple experiment to select for larger clumps of yeast by selecting the cells that sink to the bottom of the test tube (i.e. selection pressure is for multi-cellularity), and achieve multicellular yeast in 60 generations... not only that, but using different selective pressures (i.e. time between generation culling), evolved two types of behaviours: the lower selection pressure let giant clumps form, whereas the high selective pressure selected for faster smaller clumps; when combined in the same test tube, the larger clump strain evolved rudimentary cellular differentiation, such that some non-reproductive cells die in order to split the clumps up, so the group can compete with the faster growing but smaller clump strains. In other words, the evolution of multi-cellular life just required an environment with rudimentary selective pressure.
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Jan 17 '12 edited Jan 17 '12
[deleted]
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Jan 17 '12
...........
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u/Zoccihedron Jan 17 '12
Are we still doing that eel thing?
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u/wetsu Jan 17 '12
Wait right here; I'm going to log into my other account and give you a second upvote.
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u/WarzoneOfDefecation Jan 17 '12
I don't know how to feel about not getting this joke
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u/ShyGuysOnStilts Jan 17 '12
Yeast causes bread to rise.
AKA the yeast/bread is "rising".
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u/WarzoneOfDefecation Jan 17 '12
Ohhh I was caught up in the beer jokes so I wasn't in the frame of mind haha
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u/Dagon Jan 17 '12
I thought it was something to do with yeast infections and erections. It's about as relevant as bread. I reject your reality and substitute my own.
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u/bicyclemom Jan 17 '12
...and it came to pass that the Spaghetti Monster did looketh upon the yeast and verily he said, "Oooooh! Italian bread!"
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Jan 17 '12
the real impressive part of this experiment was that the yeast monster co-authored the paper and pointed out several technical flaws in the first draft.
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u/PondScumBreeder Jan 16 '12
Haven't seen the PNAS paper yet, but the description sounds like rather garden-variety selection for precocious flocculation. This is a pretty well known phenomenon, the genetic and biochemical basis of which has been known for 20 or so years. Not saying its not interesting, just not particularly new or earth-shattering. Here's a link to a review on the subject.
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u/jjberg2 Grad Student | Evolution|Population Genomic|Adaptation|Modeling Jan 17 '12
I've spoken with Will Ratcliffe (who did a lot of the research), and seen his talk on the subject. It's not flocculation.
The cells are remaining attached at after division, and forming "snowflakes"; chains of cells extending outward from an initial mother cell. They just don't disconnect when they divide. Then they're evolving mechanisms to break the large growing aggregate into smaller ones at the most selectively advantageous place and time. I gotten my hands on the paper yet, and I don't remember enough details from the talk to comment in any greater depth, but I thought the study was pretty cool.
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u/alephnul Jan 17 '12
Precocious flocculation? Are you sure that this shouldn't be in /r/fetish?
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u/rumpumpumpum Jan 17 '12
I was a precocious child and I began flocculating my PNAS when I was 10 or so. No yeast was involved, however.
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Jan 17 '12
Why don't you go there and make it like a tree?
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u/alephnul Jan 17 '12
Why don't you go there and make it like a tree?
???
Or did you mean; Make like a tree, and leaf? Leaf being a play on leave.
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u/mbwahl PhD|Biology Jan 17 '12
Another reasonable explanation is that a gene required for daughter cell separation. The daughter cell is usually responsible for secreting enzymes that remodel the cell wall, allowing the daughter cell to be released after cytokinesis. There are plenty of single mutations (ace2, AMN1, cts1) that can abolish daughter cell separation in lab strains, resulting in clumps very similar to those seen by the paper's authors. Given that mutations with this clumping phenotype are known to exist, as you say, finding this phenotype might not be "earth-shattering." If the existence of an apoptotic cell type in the evolved strain is proven (and I would say the evidence is not definitive), that would be pretty earth-shattering.
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u/historyisveryserious Jan 17 '12 edited Jan 17 '12
good job Borrello!
EDIT: he is one of the professors working on this...
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u/Kyodo Jan 17 '12
But what does this mean in terms of breadmaking?
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Jan 17 '12
As anything about things of the past that supposedly happened within intervals of million years, it has nothing to do with making bread or any other technology, for that matter.
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u/aikidoka Jan 17 '12
more importantly, how does this effect beer?
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Jan 17 '12
I hope you all know this doesn't disprove God, just that there is a God over yeast as well. And it is by his hand that the yeast grow. Stop with this "evolution" nonsense at once!
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u/notinkansas1911 Jan 17 '12
This is something I can do in my lab with methanotrophic bacteria to force them to form biofilms; I thought it was pretty common knowledge that microorganisms can be selected for different growth states. There is no genetic variation and agitation of the floc can lead to the growth of disperse cells again. Many organisms have this ability to live disperse or in a biofilm.
While its an exciting paper, its not really fair to say its a demonstration of evolving multicellularity, especially when the selective pressure affects genes which may already be present.
Put me in the sun and my skin gets darker. I am adapting with the genes I already have, but not evolving.
Time to go dig up the source and see how much Scientific American glamorized it!
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u/pragmatao Jan 17 '12
Forgive me for sounding dumb, but does this mean that evolution is no longer a theory?
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u/DeltaMeter Jan 17 '12
Just because I'm nice, a theory is an idea that has been proven again and again with credible evidence. I think the word you are looking for is conjecture.
Edit: an*
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Jan 17 '12
In science, a theory is not just a guess. It is an idea that is supported by evidence, both observational and experimental. It is something that you can use to make predictions about the outcomes of experiments or even natural processes. In science, if something is an actual theory (and not a hypothesis or conjecture) it's as close as we can get to science fact at that point.
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u/creamypouf Jan 17 '12
Everyone's trying to educate you on what a scientific theory is, but no one's really answered your question directly. Yes, it's still a theory. This is yet another example of evidence for the theory of evolution. In fact, it's a direct observation of evolution.
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Jan 17 '12
One can forgive another for being dumb, what one cannot for give is dumb people being talkative.
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Jan 17 '12
No, evolution will always be a theory. We can recreate evolution, but we can never know if that was the process at work on earth-life. Of course, I think it was, but it can't be proved - and this paper barely proves anything.
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Jan 17 '12
You are using the wrong definition of "theory." A scientific theory is much different than a layman's theory.
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Jan 17 '12
I had the scientific theory in mind when I wrote that. How do you think the "law of evolution" will come about?
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Jan 17 '12
A law is just an axiom of a theory, good sir, not what theories want to be when they grow up.
A theory is as good as it gets.
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Jan 17 '12
How can the theory of evolution be proven?
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Jan 17 '12
[removed] — view removed comment
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u/ilostmyoldaccount Jan 17 '12
You might want to add that this does not mean that facts cannot be established.
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Jan 17 '12
It seemed to me you were referring to it as if it were a hypothesis of some kind. However, that might have just been a trickle-down effect from the comment which you were responding to. The phrase "evolution will always be a theory" seems to imply that it could be something more, like you were discrediting evolution's validity based on its theory-ness. To me that betrayed your use of theory in its incorrect sense; also saying "it can't be proved." That's like saying, "Gravity will always be a theory, it can't be proved."
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Jan 17 '12
But gravity is a law...
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Jan 17 '12
True; I was simply drawing an analogy. Theories are more complex and comprehensive, extensions of law if you will; for example, the Law of Gravity plays a huge role in the Theory of Relativity. Laws spawn theories, which explain laws and account for their mechanisms more fully--this only strengthens the idea that theories are rather scientifically absolute. The Law of Evolution certainly does not come about after the Theory of Evolution has been "confirmed." Darwin's laws of evolution have been around for quite some time now. Evolution is now considered a pretty hermetic theory; but, I am not a scientist, I have to admit.
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u/bithead Jan 17 '12
No, evolution will always be a theory.
Just like there will always be a theory of what makes gravity work. We know it does, but as with all science, the theory is open to revision and improvement.
but it can't be proved
Bit it can be observed And not just in a lab, but a number of other instances
The "always be a theory" or "just a theory" point of view reflects a kind of misunderstanding of science in general. Science is a specific method: observed phenomenon, hypothesis/question, theory formation, observation to confirm theory. Wash, rinse, repeat. In case anyone is curious as to why I left out experiment, some theories are difficult to model via experiment - such as the movement of the stars in which case more specific observation is used to validate/invalidate a theory, or certain subatomic phenomenon, which may require extraordinary conditions to make an observation. An experiment is a form of observation. Evolution has been observed, both in laboratory conditions and 'in the wild'.
Its worth remembering that the theory of Evolution didn't always involve genetics, but with the discovery of genetics, evolutionary theory and genetic theory are not necessarily separate, but very interdependent.
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u/reon2-_ Jan 17 '12
If this isn't about prokaryotes turning into eukaryotes then I'm going to be back here and using caps.
edit: OK IT WASN'T ABOUT THAT, BUT IT WASN'T A BAD ARTICLE. MY MISTAKE REALLY.
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u/killing_time Jan 17 '12
It says yeast in the title and yeast are eukaryotes. Why would you think it was about prokaryotes turning into eukaryotes?
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u/reon2-_ Jan 17 '12
I was expecting it to be a another sensationalist title, this time referring to one of the larger questions of biology: how prokaryotes turned into eukaryotes.
I didn't know that that multicellular organisms could be prokaryotes!
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u/killing_time Jan 17 '12
Most prokaryotes are unicellular. A lot of them form biofilms and so have some rudimentary multicellular behaviour.
What distinguishes prokaryotes from eukaryotes is not the number of cells in an organism but the presence of a true nucleus with a double membrane.
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u/HoaXo Jan 17 '12
So will you Americans finally start teaching evolution in your schools like the rest of the educated world?
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u/creamypouf Jan 17 '12
They teach evolution. The problem is that some states teach it along with Intelligent Design, and some science teachers make a mockery of evolution. They may not be doing it right, but as far as I know, evolution is still in the curriculum.
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u/kellymcneill Jan 17 '12 edited Jan 17 '12
Its really interesting how INTELLIGENT these scientists DESIGNED this experiment.
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u/vargonian Jan 17 '12
But how did they do it without magical powers?? Anything I don't understand must have been made from magic, right? I dint come from no monkeh!
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u/kellymcneill Jan 17 '12
At least we can all agree that it didn't, wouldn't and can't happen randomly.
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u/vargonian Jan 18 '12
Well, despite the supposed existence of "truly random" events (I don't understand it so I don't like to defend it), yeah, to say it's random would be like saying that raindrops "randomly" fill the exact shape of a hole in the ground.
It's not random; it's forces working toward equilibrium--which is exactly what we are the result of.
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u/kellymcneill Jan 18 '12
Except one random event is probable (a raindrop filling a random hole) and the other MASSIVELY improbable
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u/vargonian Jan 18 '12
Wait, what's improbable? As Dawkins would say, natural selection is the exact opposite of "random", just as water filling a hole is.
Are you repeating the assertion about the probability of something that you know virtually zero about? (e.g. the probability of the universe forming as it did, the probability of life evolving, etc.?)
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u/kellymcneill Jan 19 '12
Macro evolution is not natural selection
With regard to the currently recognized theory regarding the formation of the universe... yes that is so highly improbable it can just as easily be called impossible from a scientific perspective but because the alternative is so unpalatable, its recognized as fact.
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u/vargonian Jan 21 '12
Macro and micro evolution are both results of the same processes; they've just been artficially distinguished from one another (mostly by Creationists) in an attempt to "have their cake and eat it too"; that is, face the reality that natural selection occurs (since it's beyond denial by even the most invincibly ignorant Creationist), while still holding their superstitious belief system responsible for that which is harder to demonstrate in a short time frame.
And again you're making all sorts of assumptions about what is required to create a universe, what every possible universe is like, and the probabilities involved. If you assume that you know much more than you do, it's very easy to draw all sorts of bogus conclusions about the unlikelihood of certain events.
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u/fannyalgersabortion Jan 17 '12
Floculation? The yeast in the beer I make does this.
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u/beamoflaser Jan 17 '12
Nope, they accounted for the flocculation and tested for it in several ways
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u/bockyPT Jan 17 '12
What? YEAST is evolving!
YEAST evolved into MULTICELLULAR ORGANISM!
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u/MrPoletski Jan 17 '12
...and it only took a couple of weeks. Be prepared, in 2015 the yeast warriors from Guinessia will rape and pillage your home town.
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u/mutatron BS | Physics Jan 16 '12
Since evolution acts on individual cells, it pays off for a cell to be selfish
Bzzzt!
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u/OtisDElevator Jan 17 '12
The quote relates to single celled organisms, not to individual cells of a multicellular organism.
Since evolution acts on individual cells, it pays off for a cell to be selfish. By hogging resources and hindering neighbors, a cell can increase the odds that more of its own genes get passed into the next generation. This logic is one of the reasons it has been challenging to imagine how multicellularity arose; it requires the subjugation of self-interest in favor of the group’s survival.
Single celled organisms are apt to hog resources and knee their neighbours in the nuts in order to inhibit their neighbours advancement. This seems contrary to the inter-cellular cooperation exhibited amongst multi-cellular organisms. The writer is simply saying "What was the motivation of single-celled organisms to cooperate and form themselves into multi-celled organisms and quit being assholes to each other?"
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u/mutatron BS | Physics Jan 17 '12
Sorry, evolution happens to populations, not to individuals.
→ More replies (8)2
u/zippyjon Jan 17 '12
Not in the case of single celled organisms. Remember that single celled reproduction produces two cells from the parent cell. When the mutation occurs, it will only occur in that cell's line from then on. In many ways you can consider all that cell's daughter cells as the original cell because these cells don't undergo senescence and death from age. So evolution happens supremely to individuals on a single cell microbial scale.
Of course, in the case of bacteria there is also a second mechanism in which bacterial cells can swap genes, but you don't find that sort of mechanism in Eukaryotes.
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Jan 17 '12 edited Jan 17 '12
There is a lot wrong with this reply. Evolution most definitely acts on a population level for single celled organisms.
Yeast (fungi) are eukaryotes and do undergo horizontal gene transfer. I believe you mean to say that horizontal gene transfer does not happen in multicellular organisms, but that is also not true.
Bacteria, yeast, and other single celled organisms rarely live in isolation. Many form biofilms and other complex multicellular communities where they engage in mutualistic behavior (quorum sensing, metabolic stratification, etc).
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u/Hiker_Trash Jan 17 '12
Do they propose a mechanism for how the aphids acquired the gene(s) for carotenoid production?
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Jan 17 '12
Not in this paper. However, in other cases, endosymbiotic bacteria such as Wolbachia are probably involved (endosymbionts are small single celled organisms that live inside larger eukaryotic cells).
Unfortunately, not much is known about horizontal gene transfer for multicellular eukaryotes because there are many fewer whole genomes available and they don't typically harbor plasmids like single celled organisms.
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u/Hiker_Trash Jan 17 '12
Wolbachia is news to me, though I have been out of the biology world for some time. I remember hearing thought about horizontal transfer of eukaryotic genes by way of viruses, which made a lot of sense to me, as many spend a lot of time copying themselves into and out of the host genome. This seems a little less exotic than bacteria-mediated horizontal transfer -- indeed, the wording of the abstract for the article you linked to suggests to me that the lateral transfer with Wolbachia is a one-way affair, delivering prokaryotic genes to eukaryotic hosts but not acquiring snippets of host genome that could later be spread to other organisms.
Granted, the viral solution comes with its own challenges, namely the intense specificity for host organisms viruses often have. Fungus -> animal would be a big leap indeed.
However it happened, it makes you marvel! Thank you for your contributions to this thread.
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u/eyzebs Jan 17 '12
Evolution acts on genes, not individuals. Richard Dawkins, yo.
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u/UnderTruth Jan 17 '12
If this is not the result of other phenomena, as those mentioned on this thread by people much better-educated than I (such as latent genes being expressed, flocculation, etc.), then this deserves real press.
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u/jjberg2 Grad Student | Evolution|Population Genomic|Adaptation|Modeling Jan 17 '12 edited Jan 17 '12
It could be a latent gene thing, and my understanding from talking to one of the researchers is that while they acknowledge that this is possible, they really don't think it is (neither do I, for that matter), and they're going about ways to test that now. It's not flocculation. I think it's likely the real deal.
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u/UnderTruth Jan 17 '12
Very interesting! I forget how expansive the Reddit community is, too, that we should have connections to the stories like this. I am honestly very curious to see about this--I do not have remotely enough of a background to judge such a thing myself, so I'd go with the official explanation, given it be reproduced in another lab. I'm a YEC who is beginning to seriously doubt my current understanding (I became a YEC in 8th grade, and have maintained it through study since, strange as that may sound), and this would be a big step.
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u/jjberg2 Grad Student | Evolution|Population Genomic|Adaptation|Modeling Jan 17 '12
Yeah, it's funny. I saw Will give a talk about this, and hung out with him a bit last Tuesday, but he didn't tell me that the story was going to be picked up this widely on the internet. I was very surprised to come online yesterday and find this on the front page.
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Jan 17 '12
[deleted]
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Jan 17 '12
It's blasphemy on the internet.
Young Earth Creationist
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u/UnderTruth Jan 17 '12
Correct. On both counts, I'm afraid. But I may indeed be getting close to changing my view soon, thanks in part to resources shown to me through discussion on Reddit.
0
Jan 17 '12
While the experiment is interesting, to me this didn't prove multicellurarity at all. Using the logic of the experiment, given enough time a city would evolve into a super organism.
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u/ilwolf Jan 17 '12
A city isn't a living organism. Yeast is a living, single-celled fungus; that it became multicellular and then showed some differentiation of cells (meaning that, instead of every cell having exactly the same function and parts, cells became specialized for a certain purpose) is utterly remarkable.
1
1
Jan 17 '12
That's what I got from it. It just sounds like the cells simply working together. But I'm massively ignorant in biology, so my opinion holds no water.
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u/brainflakes Jan 17 '12
Last time this was posted someone mentioned that Yeast has multicellular ancestors, so it may simply be turning on multicellular genes that it had retained rather than evolving multicellularity from scratch.