Scientists reveal driving force behind evolution

 
According to a press release from the University of Liverpool (UK), their scientists have revealed the driving force behind evolution. It's not just adaptation that drives evolution but a special form of adaptation ...

Scientists at the University of Liverpool have provided the first experimental evidence that shows that evolution is driven most powerfully by interactions between species, rather than adaptation to the environment.

The "breakthrough" has been recently published in Nature (Paterson et al., 2010). Here's the abstract.

The Red Queen hypothesis proposes that coevolution of interacting species (such as hosts and parasites) should drive molecular evolution through continual natural selection for adaptation and counter-adaptation. Although the divergence observed at some host-resistance and parasite-infectivity genes is consistent with this, the long time periods typically required to study coevolution have so far prevented any direct empirical test. Here we show, using experimental populations of the bacterium Pseudomonas fluorescens SBW25 and its viral parasite, phage Φ2, that the rate of molecular evolution in the phage was far higher when both bacterium and phage coevolved with each other than when phage evolved against a constant host genotype. Coevolution also resulted in far greater genetic divergence between replicate populations, which was correlated with the range of hosts that coevolved phage were able to infect. Consistent with this, the most rapidly evolving phage genes under coevolution were those involved in host infection. These results demonstrate, at both the genomic and phenotypic level, that antagonistic coevolution is a cause of rapid and divergent evolution, and is likely to be a major driver of evolutionary change within species.

Imagine that—phages evolve to infect bacteria and bacteria evolve to resist infection. Is that the sort of "breakthrough" that merits publication in Nature and spectacular headlines about new driving forces in evolution?

Steve Paterson seems to think so, according to the press release.

Dr Steve Paterson, from the University's School of Biosciences, explains: "Historically, it was assumed that most evolution was driven by a need to adapt to the environment or habitat. The Red Queen Hypothesis challenged this by pointing out that actually most natural selection will arise from co-evolutionary interactions with other species, not from interactions with the environment.

"This suggested that evolutionary change was created by 'tit-for-tat' adaptations by species in constant combat. This theory is widely accepted in the science community, but this is the first time we have been able to show evidence of it in an experiment with living things."

The Red Queen Hypothesis has been around for a long time and it's a perfectly reasonable explanation for arms races. I find it difficult to believe that this paper is the first demonstration of this phenomenon. I find it even more difficult to believe that "most" adaptations are the product of "co-evolutionary interactions with other species."

I have a proposal for regulating university press releases. I think every one of them should be accompanied by a short statement such as the following: The authors of this paper have been consulted and they affirm that this press release is an accurate summary of the work that has been published. They are all prepared to stand behind the statements in this press release.

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[HatTip: RichardDawkins.net]

Paterson, S., Vogwill, T., Buckling, A., Benmayor, R., Spiers, A.J., Thomson, N.R., Quail, M., Smith, F., Walker, D., Libberton, B., Fenton, A., Hall, N., Brockhurst, M.A. (2010) Antagonistic coevolution accelerates molecular evolution. Nature. 2010 Feb 24. [Epub ahead of print] [doi:10.1038/nature08798]