Did recent yeast experiment really shed much light on multicellularity?
| January 23, 2012 | Posted by News under Culture, Darwinism, News |
Recently, a research group generated a great deal of interest in their claim that we are much closer to understanding multicellularity because of a recent experiment with yeast.
At Wired’s story, the first commenter wanted to know. “Now can we sterilize the creationists?” (55 likes) See also, for example, Nature, National Science Foundation, and The Scientist, where Jef Akst reports (January 16, 2012),
Using an artificial selection paradigm, researchers watch as unicellular yeast evolve into snowflake-like clusters with distinct multicellular characteristics.
In as little as 100 generations, yeast selected to settle more quickly through a test tube evolved into multicellular, snowflake-like clusters, according to a paper published today (January 16) in Proceedings of the National Academy of Sciences. Over the course of the experiment, the clusters evolved to be larger, produce multicellular progeny, and even show differentiation of the cells within the cluster—all key characteristics of multicellular organisms.
However,
But this is just one experiment under admittedly contrived conditions. “What remains to be seen for me is how relevant is it to actual transitions to multicellularity,” said Srivastava.
Indeed, the authors of the PNAS study admit that selecting for yeast cells or clusters that settled most quickly isn’t exactly a “natural” selection pressure. But there could be some important lessons here, Ratcliff insisted. “If we really understand the way that multicellularity can evolve, then that gives us a lot of insight to how this could have occurred in the past,” he said.
Mike Behe offers a different perspective on the yeast in “More Darwinian Degradation: Much Ado about Yeast” (Evolution News & Views, January 23, 2012):
The authors repeated three steps multiple times: 1) they grew single-celled yeast in a flask; 2) briefly centrifuged it; and 3) took a small amount from the bottom of the flask to seed a new culture. This selected for cells that sedimented faster than most. After a number of rounds of selection the cells sedimented much faster than the beginning cells. Examination showed that the fast-sedimenting cells formed clusters due to incomplete separation of replicating mother-daughter cells.
The cell clusters also were 10% less fit (that’s quite an amount) than the beginning cells in the absence of the sedimentation selection. After further selection it was seen that some cells in clusters would “commit suicide” (apoptosis), which apparently made the clusters more brittle and allowed chunks to break off and form new clusters. (The beginning cells already had the ability to undergo apoptosis.)
So, in his view, it is a general loss of fitness that caused the cells to cling together or break apart.
Incidentally, yeast cells are known to act as colonies at times.
A difficulty that occurs to some laypeople is this: The fact that generally unicellular life forms may sometimes benefit from acting as a colony or a combine of some kind does not get to the heart of multicellularity.
What most of us mean by multicellularity is more like the cat on the sofa than the yeast colony or the amoebic slime mold.
Every cell of the cat – neuron, heart cell, kidney cell – is not only specific to a cat but specific to that particular cat. Apart from human veterinary heroics, most of those cells might not even survive in another cat, let alone if they were ejected from the cat onto the floor. Now that’s multicellularity. The feline cells live and die in, by, and for one specific cat.
And how many cats are there in the world?
That’s the level of organized complexity for whose origin we need to account if we want to understand the origin of multicellularity. Not the – usually dispersable – associations of unicellular fungi and amoebas.
7 Responses to Did recent yeast experiment really shed much light on multicellularity?
Leave a Reply
You must be logged in to post a comment.
At least it isn’t a rehash of the argument that pressing milk curds together represents a proof that cheddar wheels will write sonnets.
And one neo-Darwinist had the audacity to accuse me of having ‘faith’ for pointing out that this will turn out to conform to the principle of genetic entropy just as all the other examples by Lenski, and others, do (Behe; First Rule of Adaptive Evolution). Perhaps I do have a bit of ‘faith’, but if so, it takes far more ‘faith’ to believe something with no historical precedence, as he does for evolution, than it does to believe that the laws of science will continue to hold throughout nature, including the biological realm!. i.e. ‘genetic entropy’
News:
From the article:
And in only two weeks!
So I bothered to read the article. I take you’re not aware of what Brewer’s Yeast and yeast flocculation are about? All they’ve done is turn beer yeast into champagne yeast. And thank Darwin, since we can start producing champagne now!
So much for my earlier statement on cheese curds.
An author responds to a youtube creationist:
http://blog.lib.umn.edu/denis0.....e_evo.html
Interesting, the authors of the yeast paper apparently believe that God, in the biggest miracle mankind has ever witnessed, raised Jesus from the dead (since they quote Jesus to defend their position!), yet they believe that processes that degrade preexisting cellular abilities are proof that God cannot create life in the first place?!? And of all the gall of Darwinists to exhibit, the authors had the audacity to quote scripture on hypocrisy in response to the ‘creationist’!
Now you just can’t make this stuff up! 
Notes:
They alluded to ‘thousands of papers’ that support neo-Darwinian evolution, yet, under the hood, we find:
And in spite of the fact of finding molecular motors permeating the simplest of bacterial life, there are ZERO detailed Darwinian accounts for the evolution of even one such motor or system.
The following expert doesn’t even hide his very unscientific preconceived philosophical bias against intelligent design,,,
Yet at the same time the same expert readily admits that neo-Darwinism has ZERO evidence for the chance and necessity of material processes producing any cellular system whatsoever,,,
And since the authors brought up a quote from Jesus to defend their hypocrisy of science mixed with hypocrisy of metaphysics, let’s briefly, and ‘scientifically’, examine Christ’s actual position within reality;
(,,,The ‘mathematical endeavor’, to unify General Relativity with Quantum Mechanics, has been fraught with extreme difficulty. Here is, I believe, the main ‘mathematical difficulty’,,,)
(,,,Moreover, this extreme ‘mathematical difficulty’, of reconciling General Relativity with Quantum Mechanics into the much sought after ‘Theory of Everything’, was actually somewhat foreseeable from previous work, earlier in the 20th century, in mathematics by Godel:,,,)
(,,,Moreover when we allow consciousness its proper role in quantum mechanics:,,,)
(,,,We then find a very credible reconciliation between General Relativity and Quantum Mechanics which, very unlike the multiverse conjecture, actually has some very impressive empirical evidence backing it up,,,)
(,,,Thus, when one allows God into math, as Godel clearly indicated must ultimately be done to keep math from being ‘incomplete’, then we find that there actually exists a very credible reconciliation between Quantum Mechanics and General Relativity into a the much sought after ‘Theory of Everything’! Yet it certainly is a ‘Theory of Everything’ that many dogmatic Atheists will try to deny the relevance of.,,, As a footnote; Godel, who proved you cannot have a mathematical ‘Theory of Everything’, without allowing God to bring completeness to the ‘Theory of Everything’ in the first place, also had this to say,,,)
When I saw that story, my first thought was, “Another controlled experiment trying to prove the power of chaos.” Which might not necessarily invalidate it…But then I also thought, “And what does this have to do with fish evolving into land animals, and land animals into George Carlin?” For decades, Darwinists have trumpeted genetic mutation as the key to evolution, yet it is clear that in this experiment, something different was taking place.
First, they relied on selective breeding rather than mutation, which is to say that they gathered a pack of wild dogs and thinned out the gene pool until nothing was left but an ugly chihuahua.
Second, as a result of this selective breeding, the final product was unable to reproduce without complications. I don’t know enough about biology to know whether the faulty separation process causes actual mutations to the underlying genetic code, and it seems that the scientists didn’t go into detail on that issue. But let’s say that there is a change. Even so, we’ve got a problem.
Again, let’s go back to the standard explanation of how genetic mutations are the cause of complex life. The idea is that every so often, copying errors occur in the genetic code. Most of those errors are bad, but some are beneficial, and the beneficial ones survive to the next generation because they give the animal an advantage.
How is that different from the yeast? Because the selection was not for a beneficial trait in the messed-up, partially unseparated yeast offspring. Rather, what was selected was the fast-sedimenting yeast parent cells. The grotesque Borg-like offspring were just a side effect.
If we applied that concept to the broader evolutionary process, it would mean that complex creatures have come to be, not because their complexity is beneficial, but because their parents had the distinction of A)Outliving their peers and B)Suffering from reproductive problems.
Am I saying that complicated explanations are necessarily false? No. But the burden of proof remains on the shoulders of the Darwinists to show us why we should believe their wild theories.