Single Cells Evolve Large Multicellular Forms in Just Two Years

@thoughtful , I do think @Dan_Eastwood or someone should produce the quote.

As I recall, it wasn’t necessarily about frogs, but he did equate the development of an organism with the evolution of species.

But, as @Joel_Duff and others have pointed out, if a single pair of created kind can evolve into what ever number of species in four thousand years, why not in millions of years?

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But do they lack “specialization and differentiation”? It seems to me this comes in degrees. One could argue that even tiny changes in expression is a degree of and therefore a form of differentiation. Do cells in the core of the multicellular aggregate express their genes in exactly the same way as those on the surface? If I know anything about cell biology and gene expression I’m quite certain they don’t.

The more interesting question in that vein then, in my view, is whether or to what extend any of these possible differences in expression have evolved in response to the selection pressure, and what would happen under continued evolution under selection for these sorts of clumps of cells.

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I think you meant to tag a different Dan @dsterncardinale? Also wanted to let him know my posts were approved out of order. I had first said I’d look up the quote and then mentioned I couldn’t find any similar reference.

This is a different topic and an interesting one but my response is this non-response because I don’t have the time to engage it in a meaningful way in a new thread. Maybe it was meant as a rhetorical question anyway. :slightly_smiling_face:

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Fair point. I thinking having the quote, which I am sure exists, would be good. @dsterncardinale

I’m sorry, it was in “On the Origin of Eukaryotic Species’ Genotypic and Phenotypic Diversity” in “Answers Research Journal”, not “Replacing Darwin”. My apologies. See figure 2.

The wood frog ( Lithobates sylvaticus ) develops from a single cell to a sexually mature adult in less than three years, undergoing massive phenotypic transformation in the process. By contrast, over the course of 4365 years, the 37 cat species that exist today arose from a common felid ancestor—a much smaller level of phenotypic change. Thus, producing extensive phenotypic species diversity in a few thousand years is not an unreasonable postulate.

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@thoughtful , there you have it. Thanks for asking for the reference. As you can see, he misremembered the citation, but his paraphrases was true to an actual quote from Jeanson.

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The figure can’t be forgotten either:

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From the Jeanson article referenced by Dan…

In contrast, the origin of the various cat species in the family Felidae from a common ancestor on board the Ark (Pendragon and Winkler 2011) took over 4000 years.

By contrast, over the course of 4365 years, the 37 cat species that exist today arose from a common felid ancestor

House cats, lions, cheetahs, and leopards are broadly found among ancient murals and statuary, animal mummies, and document references, from Egypt, Cyprus, China, and Mesopotania going back to Gobekli Tepe. A diverse historical and archeological record of modern cats extends well past 4000 years.

Not only is it blindingly obvious from this that 4000 years is not available, but the accounting must include the greater number of long extinct species such as the saber-toothed cats.

Nathaniel Jeanson holds a PhD in cell and developmental biology from Harvard University. Lisle earned a PhD in astrophysics at the University of Colorado in Boulder. If the two of them together writing a research paper published in a supposedly peer reviewed creation journal are oblivious to such common knowledge, then what a waste of education. Why should their ideas on heterozygosity be seriously engaged with when led with such farcical drivel?

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Thanks for finding it.

I haven’t thought about cellular differentiation before. I had to reread the thread and article to make sure I understood it correctly.

Since phenotypic diversity was brought up :laughing: - couldn’t we say (perhaps @scd was saying this) we’re just seeing the phenotypic diversity of the genetics of a unicellular organism, in this case yeast? Diversity which sometimes can include multicellularity?

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This should rank up there with Comfort’s Banana as one of the silliest claims ever.

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Agreed! :smiley:

No, because the new phenotype required trans-generational genetic changes. Some already existing yeast cell didn’t just respond to the environment by turning on certain genes(in the same way you smelling a nice meal might turn on saliva glands in your mouth), but instead the change only occurred after multiple consecutive generations of cells suffering mutations that were subject to an environmental selective pressure.

Heritable mutations had to occur, and this is not a developmental process but an evolutionary one by definition.

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I did the math on this once or twice. We have records from Middle Kingdom Egypt with all the cats already differentiated, but lacking the extinct ones. Which means going from the Ark to Middle Kingdom, a span of just a few hundred years, requires the evolution of about 150 species (I think it’s about 150 total? But check my memory) from a single pair, along with the extinction of most of those species.

That’s putting the flood at about 2400 BCE, and Middle Kingdom at about 2000 BCE. Four hundred years.

But wait! There’s also an ice age in there. Busy couple of centuries.

So not only does Jeanson’s figure make no sense as is, the timeline is 10x too long and the number of species is several times too few. It really is a delightfully terrible argument.

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I’m not saying it’s not an evolutionary process. I guess I’m asking why a new phenotype in a unicellular organism (occuring because of mutation and selection) is cellular differentiation and not just a new phenotype. Because you want it to be? What I was looking up yesterday was suggesting cell differentiation in multicellular organisms uses epigenetics. I know nothing about that, but shouldn’t some evidence of that be shown before a case can be made?

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No, the mutations could have occurred long before. Please stop with this idea that existing variation isn’t driving evolution and that only new mutations can.

Had to? No, heritable variation merely had to exist. The population isn’t waiting around for new mutations to occur before evolution can happen.

Only a minority does.

Most differentiation doesn’t, which is why scientists have learned a lot about differentiation before epigenetic mechanisms had been discovered.

Let’s leave medical diagnoses to the professionals, please.

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Not in this case. The “snowflake” yeasts were not a phenotype selected out of some pre-existing population by shifting gene frequencies. This experiment began from a clone, the cluster size expanded gradually over 3000 generations:

Results

We began our experiment by engineering a unicellular isolate of S. cerevisiae strain Y55 to grow
with the snowflake phenotype by deleting the ACE2 open reading frame (25).

Materials and Methods

Long-term evolution experiment. To generate our ancestral snowflake yeast for the long-term
evolution experiment, we started with a unicellular diploid yeast strain (Y55). In this yeast, we
replaced both copies of the ACE2 transcription factor using a KANMX resistance marker
(ace2::KANMX/ace2::KANMX) and obtained a snowflake yeast clone (see (25) for a detailed
description of strains and growth conditions, including measurements of oxygen concentrations
in growth media).

In reference 25 we find:

Starting with a single diploid clone of strain Y55 (a unicellular yeast), we selected for rapid settling through liquid media in 10 replicate populations.

Whole thing begins with a single cell. All subsequent variation in a population must be due to mutation.

Mercer I have no idea why you’re telling me this, as I have made no such statement.

Incidentally, people who are experts in exactly this question are saying that it is the people who are relying on appeals to selecting acting on standing genetic variation to change frequencies of alleles in populations without fully appreciating the extend to which evolution is driven by mutation that needs to stop doing that:

Before anyone comes around and cries uncle, please note that nobody here is suggesting that the phenomenon of changing frequencies of alleles in a population due to selection does not occur. Of course it does, but either of the two extremes(changing frequencies vs waiting for new mutations) fails to capture the full scope of evolutionary change. Both phenomena are relevant to understanding evolution.

And in this specific case, the phenotypes that had evolved at the end of this 3000-generation experiment did (and could not) have existed when the experiment began.

When starting isoclonally it most definitely is in fact doing exactly that. When the population begins from a clone, variation has to arise mutationally and selection then has to wait for novel phenotypes favor over others.

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Then you are correct and I am incorrect. Apologies.

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It’s so nice to have conversation between reasonable people. :slight_smile:

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“Hey I’m just asking questions”.

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