Test Tube Yeast evolves to be Multicellular

[Firepac]

My sources say that this is selective breeding, not evolution. And that the genetic information for yeast to become multicellular did not evolve, it was already in the genome. The study was published on January 16th, but the experiment was done last June so the skeptical scientists have had a chance to review it and make their statements.

My sources say that this isn't an example of a new kind of organism, but an awakening of a dormant ability that was already in an organism. Sorry evolutionists, that you had to get so excited. Maybe when a frog becomes a Prince naturally you can start shouting again.

:thud:

So where's your evidence that "the genetic information for yeast to become multicellular was already in the genome?"

 

[Man of Faith]

Man of Faith, one of the first things that confuses me about your post is that you say, "...this is selective breeding, not evolution." Are you insinuating that artificial selection isn't an evolutionary process? The Scientific American article was clear about this being artificial selection:



(Color added for emphasis). I'm only pointing this out because I hope you understand that the selection mechanism in an evolutionary process is fairly inconsequential in terms of finding a proof-of-concept for the evolution of a particular system. For instance, also from the article:



(Color added for emphasis). The breakthrough this study is hailing isn't an explanation of exactly how multicellularity evolved in nature -- it's that we now know it's not as difficult as might have previously been believed for multicellularity to evolve, period (e.g., regardless of whether the selection pressures are artificial or not). That's what the discovery is here.

Another chief complaint that you raise is that "...this isn't an example of a new kind of organism, but an awakening of a dormant ability that was already in an organism." I just hope that you understand that's exactly how evolution of complex systems works. New functions (such as the multicellular behavior) arise in evolution through novel uses of already existing structures and functions. In effect, your complaint is true -- but it's not evidence against evolution; but rather affirming that evolution is exactly what we're seeing here since that's exactly what we'd expect to see.

I wasn't attacking artificial selection. I understand that artificial selection is used to show that natural selection could be possible. However there has to be more to evolution than natural selection, because in order for something to be selected, it has to be there already. And if it is there already, where did it come from? If the yeast already had the ability to adapt to its environment by becoming multi-cellular, then applying the proper pressures to make it happen isn’t evolution. Where and how did the yeast get the genetic trait to become multi-cellular? That is the question. Not that it eventually could or did become multi-cellular, either naturally or artificially.

Here is the issue. Did cats and dogs evolve from other cats and dogs by selective breeding, or by random mutations and natural selection? A dog breeder uses artificial selection to produce other breeds of dogs. That shows that the dogs could possible breed naturally over time. But the genetic traits to become smaller dogs, or larger dogs, have long hair or short hair, stubby legs or long legs, long ears or floppy ears, etc… were already in the original dog, or wolf, or else they couldn’t be selected. Where did those traits come from? If they evolved, by random mutation, where is that study?

I would like to see a scientific study that shows how the yeast obtained the ability to become multi-cellular. I think that would be more of a significant find for evolution than showing that the traits were or could be selected, either naturally or artificially.

 

[Man of Faith]

So where's your evidence that "the genetic information for yeast to become multicellular was already in the genome?"

Here is the source that I was given.
Blacketer, M.J. et al. 1993. Regulation of dimorphism in Saccharomyces cerevisiae: involvement of the novel protein kinase homolog Elm1p and protein phosphatase 2A. Mol Cell Biol. 13 no. 9:5567–5581

Phenotypic switching - Wikipedia, the free encyclopedia"
Phenotypic switching (a.k.a. phenotypic dimorphism) is switching between two cell-types. An example is Candida albicans, which, when it infects host tissue, switches from the usual unicellular yeast-like form into an invasive, multicellular filamentous form.[1] This switching between two cell-types is known as dimorphism."

 

[painted wolf]

Here is a link to the actual paper... and the full abstract.

Experimental evolution of multicellularity

Multicellularity was one of the most significant innovations in the history of life, but its initial evolution remains poorly understood. Using experimental evolution, we show that key steps in this transition could have occurred quickly. We subjected the unicellular yeast Saccharomyces cerevisiae to an environment in which we expected multicellularity to be adaptive. We observed the rapid evolution of clustering genotypes that display a novel multicellular life history characterized by reproduction via multicellular propagules, a juvenile phase, and determinate growth. The multicellular clusters are uniclonal, minimizing within-cluster genetic conflicts of interest. Simple among-cell division of labor rapidly evolved. Early multicellular strains were composed of physiologically similar cells, but these subsequently evolved higher rates of programmed cell death (apoptosis), an adaptation that increases propagule production. These results show that key aspects of multicellular complexity, a subject of central importance to biology, can readily evolve from unicellular eukaryotes.

Sorry, I don't have time for any commentary at the moment, I have a busy day ahead... but I'll post my thoughts on it later in the evening if I have time.

wa:do

 

[InformedIgnorance]

However there has to be more to evolution than natural selection, because in order for something to be selected, it has to be there already. And if it is there already, where did it come from?

You do know of course that not every member of the same species has identical genetic composition right? There are variations which may arise from a number of different sources, imperfect replication (for example in the reproductive process or when replacing damagedcells), environment influences (such as the sun for example which can cause damage or changes to cells thereby changing their composition) etc.

Personally I like the idea that inter-cellular collaboration may arise as a result of game theory, where cells attempt to work for the individual good by working together for the common good... of course this would be vastly different in a population of unicell organisms, perhaps it might be something as simple as obtaining food, protein development and so forth...

 

[Meow Mix]

I wasn't attacking artificial selection. I understand that artificial selection is used to show that natural selection could be possible. However there has to be more to evolution than natural selection, because in order for something to be selected, it has to be there already. And if it is there already, where did it come from? If the yeast already had the ability to adapt to its environment by becoming multi-cellular, then applying the proper pressures to make it happen isn’t evolution. Where and how did the yeast get the genetic trait to become multi-cellular? That is the question. Not that it eventually could or did become multi-cellular, either naturally or artificially.

That objection is fair enough. I didn't know, for instance, that phenotypic dimorphism has already been documented in this species. The problem with science popularization (such as Scientific American) is that the real point can sometimes be lost. Sometime later I'll need to read the source article (I think Painted Wolf provided it) to re-evaluate the meaning of the experiment.

Here is the issue. Did cats and dogs evolve from other cats and dogs by selective breeding, or by random mutations and natural selection? A dog breeder uses artificial selection to produce other breeds of dogs. That shows that the dogs could possible breed naturally over time. But the genetic traits to become smaller dogs, or larger dogs, have long hair or short hair, stubby legs or long legs, long ears or floppy ears, etc… were already in the original dog, or wolf, or else they couldn’t be selected. Where did those traits come from? If they evolved, by random mutation, where is that study?

I think there's a "zooming" problem happening here: by that I mean that we're trying to look at a process that's grey/fuzzy like evolution, but we're used to "zooming out" to look at macroscopic processes (or lengthy processes in time) or "zooming in" to look at microscopic processes (or short processes in time), and it's easy to zoom out too far or zoom in too far to see where the genesis of new alleles, functions, and structures come from.

If we chronologically "zoom in" too far (we're just looking at a generation or two), then we might ask where this or that trait ultimately came from (as you are doing here) because a particular allele that's being selected for actually entered the population a ways back; yet simply hasn't contributed to selection pressures for whatever reason until now.

New alleles come from mutations, genetic drift, retroviruses, and other sources -- they don't necessarily immediately start contributing to selection pressures because if might take a collection of alleles to come together before selection pressures become relevant, or because a new environment for the population causes them to become relevant, and many reasons beside.

In keeping with Canis familiaris analogies, alleles for stubby legs or longer ears or whatever might not be found in Canis lupus ancestors, yet might have been endemic to many Canis familiaris populations for hundreds of years before selection pressures even had anything to do with it. Zoom out "too far" chronologically (like getting a wider perspective on a timeline) and it might seem like the allele appeared abruptly -- zoom "in" too far and, as you are doing here, you might question where the allele ultimately came from since it's "already there" in the species.

But the point is that evolution is a fuzzy process -- it's not really possible to demarcate on some timeline "Here is the first individual with this allele" or "Here is where the species branched off." The fact remains, though, that at one point ancestors didn't carry a particular version of an allele that might be relevant to selection pressures now, even if the allele has been in the populations for hundreds or even millions of years. The allele was originated at some point (and it might even be possible to determine a timeframe when), but this is just how evolution works.

I would like to see a scientific study that shows how the yeast obtained the ability to become multi-cellular. I think that would be more of a significant find for evolution than showing that the traits were or could be selected, either naturally or artificially.

I think it's fair to ask for that specific bit of information -- in fact, I'd be interested to know, too, when these alleles entered the populations of which ancestors. However I think the question ultimately misses the "fuzziness" of evolution. I can understand why, though.

 

[painted wolf]

Saccharomyces cerevisiae in its filamentous phenotype is not multicellular but colonial. What makes this study unique is that the cells are not filamentous (no enlongation of individual cells), though the same genetic switch is likely co-opted for the "snowflake"... and that there is some division of labor.

Division of labor is the hallmark of multicellularity and very rare in unicelluar colonial organisms. The only one I know of is Volvox.
This paper shows how easy it is for a species that is already semicolonial to go all the way and potentially become fully multicellular.

Interestingly, the only reason that critters like Placozoans and Sponges are known to be genuine multicellular animals is that if you disassociate their cells, they will schootch back together to reform the same organism. With sponges, if you blend a few of them together in a blender they will still go back to their original organism... they understand "us" vs. "not us".

wa:do

 

[Alceste]

Saccharomyces cerevisiae in its filamentous phenotype is not multicellular but colonial. What makes this study unique is that the cells are not filamentous (no enlongation of individual cells), though the same genetic switch is likely co-opted for the "snowflake"... and that there is some division of labor.

Division of labor is the hallmark of multicellularity and very rare in unicelluar colonial organisms. The only one I know of is Volvox.
This paper shows how easy it is for a species that is already semicolonial to go all the way and potentially become fully multicellular.

Interestingly, the only reason that critters like Placozoans and Sponges are known to be genuine multicellular animals is that if you disassociate their cells, they will schootch back together to reform the same organism. With sponges, if you blend a few of them together in a blender they will still go back to their original organism... they understand "us" vs. "not us".

wa:do

That is bizarre. I gotta go get me a couple of sponges and a blender...

 

[Krok]

Saccharomyces cerevisiae in its filamentous phenotype is not multicellular but colonial. What makes this study unique is that the cells are not filamentous (no enlongation of individual cells), though the same genetic switch is likely co-opted for the "snowflake"... and that there is some division of labor.

Division of labor is the hallmark of multicellularity and very rare in unicelluar colonial organisms. The only one I know of is Volvox.
This paper shows how easy it is for a species that is already semicolonial to go all the way and potentially become fully multicellular.

Interestingly, the only reason that critters like Placozoans and Sponges are known to be genuine multicellular animals is that if you disassociate their cells, they will schootch back together to reform the same organism. With sponges, if you blend a few of them together in a blender they will still go back to their original organism... they understand "us" vs. "not us".

wa:do

Thanks for the wonderful info, painted wolf. Wow. Who was the cosmologist or physicist or whatever who said that the Universe is even stranger that we can concieve it to be (or something like that)? Seems the same with organisms!

Organisms (or groups of organisms?) like the Portuguese Man o' War, how does/do it/they fit into it? I know they are classified as colonies, but I don't know why?

Maybe it's time for me to start doing a course in biology. Sounds so interesting.

(..or I can glance at a creationist web-site quickly to know it all)!:sarcastic

 

[painted wolf]

Thanks for the wonderful info, painted wolf. Wow. Who was the cosmologist or physicist or whatever who said that the Universe is even stranger that we can concieve it to be (or something like that)? Seems the same with organisms!

Organisms (or groups of organisms?) like the Portuguese Man o' War, how does/do it/they fit into it? I know they are classified as colonies, but I don't know why?

Maybe it's time for me to start doing a course in biology. Sounds so interesting.

(..or I can glance at a creationist web-site quickly to know it all)!:sarcastic

They are still multicellular as each individual in the colony (called a zooid) is a multicellular critter in its own right. But how each zooid communicates and divides labor between each of them may be analogous to how single celled organism do it. But this is where the limits of my personal knowledge goes.

wa:do

 

[Krok]

They are still multicellular as each individual in the colony (called a zooid) is a multicellular critter in its own right. But how each zooid communicates and divides labor between each of them may be analogous to how single celled organism do it. But this is where the limits of my personal knowledge goes. wa:do

Thanks. So, you don't know much about them, therefore Goddidit. As a result of your lack of knowledge on the Potuguese Man o'War, the Universe was formed less than 10 000 thousand years ago and there was a flood a few thousand years ago! :drool:

PS, I still wonder why the Portuguese Man o' War is classified as a colony. It'ts so frustrating to know so little.

 

[painted wolf]

Thanks. So, you don't know much about them, therefore Goddidit. As a result of your lack of knowledge on the Potuguese Man o'War, the Universe was formed less than 10 000 thousand years ago and there was a flood a few thousand years ago! :drool:

Exactly... since science (or in this case a single scientist) doesn't know the answer to everything it must be proof that science can't know anything and therefore an collection of vague ancient stories, that claim to be directly from God, is literally 100% absolutely true.

PS, I still wonder why the Portuguese Man o' War is classified as a colony. It'ts so frustrating to know so little.

It's classified as a colony because each of the parts is technically made up of unique critters called zooids. Just like coral is a colony of zooids... but in the case of coral each zooid is separated by a shell, while in a Man o'War they are touching each other.

wa:do

 

[Firepac]

They are still multicellular as each individual in the colony (called a zooid) is a multicellular critter in its own right. But how each zooid communicates and divides labor between each of them may be analogous to how single celled organism do it. But this is where the limits of my personal knowledge goes.

wa:do

I wonder if the Portuguese Man o' War can ever evolve to become 1 organism. Has something like this happened before with other multicellular species? And if so, is the opposite possible as well?

 

[Man of Faith]

There are variations which may arise from a number of different sources, imperfect replication (for example in the reproductive process or when replacing damagedcells), environment influences (such as the sun for example which can cause damage or changes to cells thereby changing their composition) etc.

God being one of them during creation week?

 

[Man of Faith]

But the point is that evolution is a fuzzy process... The fact remains...

I like that. Evolution is a "fuzzy fact." I think I will get the opportunity to use that soon! Thanks! :angel2:

 

[painted wolf]

Well, it already technically is one organism... the various parts function as a whole.

You could say that the mutualistic relationships between animals and their gut bacteria is similar. Or certain parasites and their hosts.

I doubt it can go the other way... once you specialize that much you can't really reverse the process.

wa:do

 

[Krok]

I like that. Evolution is a "fuzzy fact." I think I will get the opportunity to use that soon! Thanks! :angel2:

Why do creationists always try to tell untruths? A fuzzy process is different to fact. People can even read what was posted. It seems like creationists can't. Ah, well, I'll put it down to a lack of quality education.:yes: Man of faith, could you define "kind" ?

 

[painted wolf]

I like that. Evolution is a "fuzzy fact." I think I will get the opportunity to use that soon! Thanks! :angel2:

Congrats Meow, you just got quote mined! :foryou:

wa:do

 

[Man of Faith]

Why do creationists always try to tell untruths? A fuzzy process is different to fact. They can't even read. Ah, well, I'll put it down to a lack of quality education.:yes: Man of faith, could you define "kind" ?

How about this, evolution is a fact with a fuzzy process, but creation isn't true because we don't know what a kind is?

 

[Tristesse]

How about this, evolution is a fact with a fuzzy process, but creation isn't true because we don't know what a kind is?

Evolution is a pretty well understood process, but creation is a bald assertion, with fallacies thrown in. It's not a matter of not understanding how a god could have created life forms, but rather that a god is a panacea, and doesn't actually solve any issues and only creates a larger mystery out of the unknown.