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Can stress force evolution?

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Asks Andreas von Bubnoff at Nautilus:

Susan M. Rosenberg, a molecular biologist at Baylor College of Medicine, quotes Adams’ “(deliciously) askew” story in a research paper on mutations in evolution as an example of how, according to standard neo-Darwinian theory, evolution does not work. Organisms, all good students know, do not generate rapid genetic mutations in response to their environment. There are exceptions, such as mutations spurred by certain chemicals or radiation. In general, though, mutations, the raw material for natural selection, accumulate slowly in dividing cells, as the result of accidental errors in the way cells copy or repair their genetic material. The environment plays a role only later, selecting the most viable mutants.

But after more than two decades of experiments with the bacteria E. coli and most recently human cancer cells, Rosenberg is challenging that central tenet of evolutionary theory. According to Rosenberg and colleagues like Robert H. Austin, a physicist at Princeton University, organisms have evolved mechanisms that enable them to drive their own evolution in times of stress. Environmental pressure can boost mutation rates rapidly, even in cells that are not dividing, enabling them to adapt more quickly to new conditions. “Stop insisting that all mutations are random and evolution is slow is the entire story,” Austin says.

Curious how offhand one can be these days, challenging a central tenet of evolutionary theory.

That said, her theory involves a lot of cognitive work on the part of an unintelligent sequence of events (we can hardly call it a process). And how many years did the sequence just happen to run, resulting in the machinery for evolution?

Colleagues don’t like Rosenberg’s idea:

Joanna Masel, an evolutionary biologist at the University of Arizona, says Austin’s death galaxy experiments provide one of the first direct experimental proofs she has seen that a complex environment with loosely connected populations can accelerate evolution.

But when it comes to modulation of mutation rates in response to environmental conditions, she and other evolutionary biologists are skeptical. First, it’s hard to show whether mutation rates are modulated by environmental conditions, says Paul Rainey, an evolutionary biologist at Massey University in New Zealand. That’s because it’s easy to miss some hidden growth period during which cells divide, in which case the mutations may still be created at the normal rate. More.

We did not think colleagues would like it. But hey, she still has a job.

Rosenberg, meanwhile, would like to produce an anti-evolvability drug, to act against cancer.

See also: What the fossils told us in their own words

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One Reply to “Can stress force evolution?

  1. 1
    Bob O'H says:

    Organisms, all good students know, do not generate rapid genetic mutations in response to their environment.

    Oh poo, I guess I was a bad student for remembering my genetics lecturers telling me precisely the opposite. This was found in the 60s: some bacteria were found to be able to increase their mutation rate under stress. It’s really really cool because it looks like Lamarckian evolution, but when you look at what’s going on, it’s perfectly explicable by evolutionary biology.

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