(September 14, 2014 at 9:12 pm)SteelCurtain Wrote: Desai's test, while really interesting, sort of oversimplifies environmental input on selection. If a 100 relatively genetically basic organisms are subject to the same environment and selected in the same method, only specific mutations will be beneficial to population selections. The important point is that genetically similar yeast can be "fit" in the same way. But it seems to me these populations of yeast were selected for the same fitness, why is it a surprise that they show similar paths to get to that fitness? And also, since when is selection pressure the exact same over multiple generations?
Very cool experiment in it's scale and scope.
To be fair, the comments also read:
"Michael Desai says: Basically I agree that in natural systems organisms will alter the environment, and that this could in principle lead to divergent selection. There are many other forces that could in principle lead to divergent selection as well. Our experiment was not designed to address all of these possibilities. Instead, we are focusing on one specific possible source of divergent pressures: the effects of initial mutations in shaping future evolutionary trajectories. We show that this specific aspect of evolutionary contingency leads to convergence rather than divergence at the fitness level.
For what it’s worth, it’s also true that in our system the yeast presumably do change the environment as they evolve, though one could argue that there isn’t as much opportunity for them to do so as might be present in a natural system."
