Tuesday, February 13, 2007

Lenski et al: Balancing robustness and evolvability

R. Lensi, J. Barrick and C. Ofria. Balancing robustness and evolvability. PLoS Biology, Vol. 4, 12, pp 2190-2193

This paper has not much to do with cancer but I have been interested in evolvability issues for a while so I decided to take a look at it. Tumour evolution has many but not all the features of the evolution involving longer time scales but its evolvability is not a thoroughly investigated topic. That is a shame because it seems that, given enough time, one would expect that tumour cells will not evolve only towards phenotypes that can take better advantage of the environment but also to genotypes that allow evolution to adapt better to that changing environment.

This paper does not explore this but something also interesting: that robustness and evolvability might be desirable but incompatible aims. Robustness can be seen as he ability to counteract change while evolvability represents the capability to adapt. In general it is true that species must strike some sort of compromise between these two abilities since organisms need the robustness provided, for instance, by the DNA repair mechanism but species need mutations that actually allow these organisms to better adapt to the environment. This is not always true and there are cases in which robustness and evolvability can go happily hand by hand. One such case is genomic redundancy. Up to a point, genomic redundancy improves robustness since functionality is kept in more than one location making it less vulnerable but also it helps evolvability since it allows duplicated genes to evolve different functions.

The general rule though is that organisms cannot be entirely robust to change in the form of genetic mutations since such an organism would freeze from an evolutionary point of view and thus subject to become extinct when a fitter rival comes around. I guess that that is a good explanation to cancer, a perfect reproduction mechanism would have not led from simple organisms to humans.

Monday, February 12, 2007

Cancer and biofuels

I have recently commented how (in my particular view, especially at the theoretical level) research in some area can be used in a different one but I guess I did not expect this: Cancer research may help biofuels.

It seems that, inspired by research done at the Fred Hutchinson Cancer Research Center in Seattle, a company called Targeted Growth is doing to corn the opposite of what oncologists do to human cancer cells taking advantage of the fact that some pathways in these two different cells are similar. The idea is to promote plant growth by overriding the genetic clock that tells the cell when to stop growing. The advantage is that plants thus modified are not transgenic (whith the load that this label carries to many consumers) and that it can lower the price of growing them as biofuels and thus promoting them as a good value alternative to oil.