Battle Between Bubbles Might Have Started Evolution

Howard Hughes Medical Institute researchers are proposing that the first battle for survival-of-the-fittest might have played out as a simple physical duel between fatty bubbles stuffed with genetic material. The scientists suggest that genetic material that replicated quickly may have been all the bubbles needed to edge out their competitors and begin evolving into more sophisticated cells.

This possibility, revealed by laboratory experiments with artificial fatty acid sacs, is in sharp contrast to a current theory of the earliest evolution of cells, which suggests that cellular evolution was driven by primordial genetic machinery that actively synthesized cell membranes or otherwise influenced cell stability or division.

The researchers, led by Howard Hughes Medical Institute investigator Jack W. Szostak, published their findings in the September 3, 2004, issue of the journal Science. Szostak and first author Irene Chen, both from Massachusetts General Hospital and Harvard Medical School, collaborated on the studies with Richard Roberts of the California Institute of Technology.

Cells are basically sacs encapsulated by bilayered membranes of fatty acids and other lipids, plus proteins. A central question in evolution is how simple versions of these cells, or vesicles, first arose and began the process of competition that drove the evolution of life.

"Most of the previous thinking about how cells grew and evolved was based on the idea of the initial evolution of structural RNAs or ribozymes -- enzymes that could synthesize membrane molecules," said Szostak. The ribozymes might have made more membrane material while the structural RNAs might have formed a cytoskeleton that influenced stability, shape, growth or division, he said. However, Szostak and his colleagues theorized that a far simpler physical process might explain why cells would compete with one another for the materials necessary to expand their size.

"We proposed that the genetic material could drive the growth of cells just by virtue of being there," he said. "As the RNA exerts an osmotic pressure on the inside of these little membrane vesicles, this internal pressure puts a tension on the membrane, which tries to expand. We proposed that it could do so through the spontaneous transfer of material from other vesicles nearby that have less internal pressure because they have less genetic material inside."

In order to test their theory, the researchers first constructed simple model "protocells," in which they filled fatty-acid vesicles with either a sucrose solution or the same solvent without sucrose. The sucrose solution created a greater osmotic pressure inside the vesicles than the solvent alone. The membranes of the simple vesicles were not as sophisticated as the membranes of today's living cells, said Szostak. However, they closely resembled the kinds of primordial vesicles that might have existed at the beginning of evolution.

When the scientists mixed the two vesicles, they observed that the ones with sucrose - in which there was greater membrane tension - did, indeed, grow by drawing membrane material from those without sucrose.

"Once we had some understanding that this process worked, we moved on to more interesting versions, in which we loaded the vesicles with genetic molecules," said Szostak. The researchers conducted the same competition tests using vesicles loaded with the basic molecular building blocks of genetic material, called nucleotides. Next, they used RNA segments, and finally a large, natural RNA molecule. In all cases, they saw that the vesicles swollen with genetic material grew, while those with no genetic material shrank.

It is important to note, said Szostak, the concentrations of genetic material that his group used were comparable to those found in living cells.

"In contrast to the earlier idea that Darwinian competition at the cellular level had to wait until the evolution of lipid-synthesizing ribozymes or structural RNAs, our results show that all you would need is to have the RNA replicating," said Szostak. "The cells that had RNA that replicated better -- and ended up with more RNA inside -- would grow faster. So, there is a direct coupling between how well the RNA replicates and how quickly the cell can grow. It's just based on a physical principle and would emerge spontaneously," he said.

According to Szostak, the next step in the research will depend on another major effort under way in his laboratory to create artificial, replicating RNA molecules.

"If we can get self-replicating RNAs, then we can put them into these simple membrane compartments and hope to actually see this competitive process of growth that we are hypothesizing," he said.

From the editor at Creationsafaris:

One of the problems with peer review is that if a few reviewers let nonsense pass, it can get published in a prestigious journal, and snuggle into the corpus of scientific literature, without opportunity for immediate refutation. Then science reporters, like eager guppies at the base of a waterfall waiting for crud to wash over, swallow it whole and regurgitate for the peasants who respect science but don’t know any better. This is soooooo stupid, it makes you wonder how Big Science can print such silliness without making the Darwin Party blush. The answer is: they have to. Their materialism pushes them to silly storytelling because they have already rejected the alternative, intelligent design. Choosing beforehand to ignore the obvious, silly storytelling is all they have available, so they dress it up in enough scientific glitter to distract attention from the pitiful plot. Computer programmers know this game. A bug is a bug, but if you dress it in a handsome suit, it is transformed into a “feature.”

One hole is sufficient to make a bubble pop, but this story has more than a wiffle ball. Wise readers, get out your baloney detectors.

Personification: It’s bad enough when evolutionists personify birds and flowers, but now they expect us to believe that bubbles compete in the evolutionary fitness game? Bubbles couldn’t care if they win or pop.

Begging the question: They assume what they need to prove, by having us believe that RNA replicating enzymes (extremely sophisticated molecular machines, called replicases) already existed. Their experiments seeded the bubbles with man-made functional RNA machinery. This is like Olympic judges ignoring a sprinter competing on a motorcycle.

Word games: The Darwin Party’s favorite euphemism for miracle, “emergence” is all over the place. Prisoner’s Dilemma: A fatbubble with RNA inside is a prison, not a factory. Once the RNA inside uses up all its food (nucleotides), it cannot evolve any further. Cells have elaborate ways to control entry and exit of materials from the external environment, but fatbubbles do not. As such, they are death traps (see 01/17/2002 commentary).

More Begging the Question: They consider a more primitive genetic material (PNA), then just assume that the more complex and difficult RNA and DNA molecules will “emerge” by Darwinian evolution, the very thing they need to prove. They say, “In contrast, a neutral polymer such as PNA (peptide nucleic acid), having no associated counterions, would be a much less effective osmolyte, a difference that may have influenced the natural selection of the genetic material itself.” Did you catch that? That’s like saying, “A Piper Cub is difficult to evolve, so maybe the difference between a Piper Cub and a 757 influenced the evolution of the jumbo jet itself.” Come again?

Card Stacking: To sneak Darwinian natural selection into the plot, they play the replication card but leave out the accuracy card. Faster or more efficient replication is useless unless it is accurate. Without accurate copying, any gains will be quickly lost due to the phenomenon of “error catastrophe” – an accumulation of errors that makes the house of cards fall flat.

Non-sequitur: They assume that bigger is better. A bigger dead bubble is still dead. It’s not evolving into a living cell. They think that since fast growth is a prerequisite for life, getting some bubbles to grow faster is a step in the right direction. It does not follow.

Yet more begging the question: They presume that one gene, a replicase, is all that is necessary. They expect sensible adults to believe that a machine that can replicate an RNA molecule (how that “emerged,” they conveniently omit) was sufficient to produce translators, transporters, energy conversion systems, and factories of molecular machines working together in harmony. If that is not a myth, what is?

Glittering Generalities: Do they really expect us to believe that bubbles that grow to a certain size in a laboratory flask can tell us anything about the origin of life? Only if the audience enjoys bedtime stories like Gullible’s Drivels.

Suggestion: By associating these irrelevant fatbubbles to the Grand Myth of Evolution, they create a mystique about them that lead us to envision marvelous bubbles evolving into fantastic living things. Disney would love to animate this, right next to the ballerina hippos.

OK, that’s enough. Time would fail us to discuss the extrapolation fallacy, the post-hoc fallacy, the misuse of circumstantial evidence, the difficulty that lipid membranes fall apart in the presence of salt (see 09/17/2002 headline), etc. One hole is sufficient. The only worthwhile observation about this story is that the authors realize that the popular “RNA World” scenario (see 07/11/2002 headline) is too complex to be credible, so they offer this putative transitional plot that is simpler, in hopes of extending the magic wand of natural selection further back into the story, as if that would help. Did it help?

It’s high time we stop letting “scientists” dazzle us with bugs in suits and bubbles that come to life. This is juvenile imagination, not science. Only intelligent design could make a fatbubble do other than what comes naturally. For those who like crossword puzzles, what’s a three-letter word for “a phenomenon incurred by exceeding the maximum sustainable membrane tension of vesicles under osmotic stress”?

Accounting for a viable cell Gets Darwinists in trouble; Without design the growth to compel, Pop goes the bubble.

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.