Thu, 21 Aug 2008 07:09:16 BST CiteULike: zwang Alon http://www.citeulike.org/user/zwang/author/Alon CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/zwang/article/1568642 <i>PNAS (14 August 2007), 0611630104.</i><br /><br />Edited by Curtis G. Callan, Jr., Princeton University, Princeton, NJ, and approved June 19, 2007 (received for review December 28, 2006)Simulations of biological evolution, in which computers are used to evolve systems toward a goal, often require many generations to achieve even simple goals. It is therefore of interest to look for generic ways, compatible with natural conditions, in which evolution in simulations can be speeded. Here, we study the impact of temporally varying goals on the speed of evolution, defined as the number of generations needed for an initially random population to achieve a given goal. Using computer simulations, we find that evolution toward goals that change over time can, in certain cases, dramatically speed up evolution compared with evolution toward a fixed goal. The highest speedup is found under modularly varying goals, in which goals change over time such that each new goal shares some of the subproblems with the previous goal. The speedup increases with the complexity of the goal: the harder the problem, the larger the speedup. Modularly varying goals seem to push populations away from local fitness maxima, and guide them toward evolvable and modular solutions. This study suggests that varying environments might significantly contribute to the speed of natural evolution. In addition, it suggests a way to accelerate optimization algorithms and improve evolutionary approaches in engineering. 10.1073/pnas.0611630104 Varying environments can speed up evolution Nadav Kashtan Elad Noor Uri Alon doi:10.1073/pnas.0611630104 PNAS (14 August 2007), 0611630104. 2007-08-16T08:29:49-00:00 2007 PNAS 0611630104 evolution http://www.citeulike.org/user/zwang/article/1307464 <i>Nature Reviews Genetics, Vol. 8, No. 6., pp. 450-461.</i> Network motifs: theory and experimental approaches Uri Alon doi:10.1038/nrg2102 Nature Reviews Genetics, Vol. 8, No. 6., pp. 450-461. 2007-05-19T03:15:41-00:00 Nature Reviews Genetics 1471-0056 8 6 450 461 Nature Publishing Group motif network review