Because evolution usually takes many generations, it is hard to tell. But two new genetic studies reveal DNA changes that took hold within the last few thousand years, suggesting that modern lifestyles have recently shaped our evolution – and are probably still doing so. "During a short time, human genomes have changed a lot," says Irina Morozova of the University of Zurich in Switzerland. "We think these changes are driven by human civilisation."
Repeated evolution of similar traits in organisms facing the same ecological challenges has long captured the interest of evolutionary biologists (1–4). Naturally occurring examples of "convergent evolution" offer new opportunities to ask about predictability in evolution. Do complex genomes mean that there are endless possibilities for adapting to an ecological challenge? Or must evolution target the same genes, or even the same amino acids in the same proteins, in order to increase the fitness and therefore survival of different species facing similar challenges? Natarajan et al. (5), on page 336 of this issue, provide an example of an integrated approach to answer these questions.
WHAT kind of force is evolution? You may see it as malevolent, benevolent or both, but chances are you will also think of it as monumental – long-term and large-scale. Over billions of years, evolution has created life on Earth from the giraffe's neck to an ape clever enough to contemplate how life evolves. Yet evolution can also be fast and furious. It is happening right here, right now – and it threatens the very future of civilisation (see "Outsmarting evolution: Fighting a force that threatens civilisation").
This year's Nobel Prize in Chemistry was awarded to three scientists who harnessed evolution in the lab. Frances Arnold, a chemical engineer at the California Institute of Technology in Pasadena, was awarded half of the prize for her work on the "directed evolution" of enzymes, proteins that catalyze specific chemical reactions inside cells. George Smith of the University of Missouri in Columbia and Gregory Winter of the Medical Research Council's Laboratory of Molecular Biology in Cambridge, U.K., shared the other half of the award for using viruses that infect bacteria to direct the selection and evolution of new proteins, including antibodies. Together, the work of the new laureates has led to improved enzymes for industrial uses, such as synthesizing fuel from plant materials, as well as a bevy of new drugs to combat cancer and other diseases.
Portfolio Online Evolution is a novel method for playing real-time strategy games through evolutionary search in the space of assignments of scripts to individual game units. This method builds on and recombines two recently devised methods for playing multi-action games: (1) Portfolio Greedy Search, which searches in the space of heuristics assigned to units rather than in the space of actions, and (2) Online Evolution, which uses evolution rather than tree search to effectively play games where multiple actions per turn lead to enormous branching factors. The combination of both ideas lead to the use of evolution to search the space of which script/heuristic is assigned to which unit. In this paper, we introduce the ideas of Portfolio Online Evolution and apply it to StarCraft micro, or individual battles. It is shown to outperform all other tested methods in battles of moderate to large size.