n a windowless room, three researchers hunker over a waist-high lab table. Dressed in white coats and latex gloves, the investigators, all members of the Washington University School of Medicine in St. Louis, get down to the business at hand: skinning frozen mice.
Of course, estimating the speed of evolution even in simple organisms is anything but simple. Viruses can evolve in a matter of generations, but, as always, the strength of the selective pressure in an environment affects how fast organisms adapt, so individuals of the same species in different environments will evolve at different rates.
The key assumption in Orr's (and Fisher's) analysis is that a single mutation can potentially alter any and all traits in an organism, including the advantageous ones, changes which likely won't become fixed in the population. This concept—that a mutation can ...
