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PhysOrg: “Darwin in a Test Tube: Scientists Make Molecules that Evolve, Compete, Mimick Behavior of Darwin’s Finches” Scientists have built a molecular system that “evolves” in the lab. But like other such systems that have gone before it, this doesn’t prove Darwin.
A team at the Scripps Research Kellogg School of Science and Technology undertook the project, using molecules in test tubes to illustrate Darwinian principles. The advantage to using molecules in the project was that they “replicate” every few minutes, allowing a much faster look at the effect of changes across “generations.”
The advantage to using molecules in the project was that they “replicate” every few minutes.
Specifically, the scientists developed two “enzymatic RNA molecules” that can compete for resources in the same environment. Each time the molecules replicate, there is a small chance it will “mutate,” arguably giving the mutated molecules new “traits.” The news release explains what then happened:
[T]hey placed the two RNA molecules together in a pot with five different food sources, none of which [the molecules] had encountered previously. At the beginning of the experiment each RNA could utilize all five types of food—but none of these were utilized particularly well. After hundreds of generations of evolution, however, the two molecules each became independently adapted to use a different one of the five food sources. Their preferences were mutually exclusive—each highly preferred its own food source and shunned the other molecule’s food source.
While this study is an interesting example of a “natural selection”-like process in the chemical world, this process does nothing to show how such molecules could have evolved into more advanced creatures. Nor does it show how one kind of plant, animal, or other life-form could have evolved into another. The difference is that these molecules have lost a great deal of ability (the ability to consume four of the foods) even as they have become more efficient at consuming one food. Even if the molecules were left replicating for years, at the end of the day they would still be RNA molecules, presumably with even less overall functionality than when they began. This indicates the reality of natural selection—and how it shows proof for the opposite of what Darwin hypothesized.
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