The Editors’Choice section of Science in October 2014 has introduced a work of Professor David Waxman from ISTBI, Fudan University, in cooperation with one of his PhD students, etc. The work entitled “Exact simulation of conditioned Wright–Fisher models” was published in Journal of Theoretical Biology, and it is commented by the editor of Science as followings: Most complex systems have an element of randomness—Even if we can describe them exactly at one point in time, we don’t know for certain where they will be next. Scientists use stochastic equations to compute the many possible trajectories these systems can take. If we constrain both end points of such trajectories, the usual approach to calculating all trajectories and rejecting those that do not end at the desired final point can be very inefficient. Zhao et al. introduced an approach in which they modified the probabilities for moving from one state to the next, so that the system was guaranteed to reach the set final state. The authors used examples from population genetics to illustrate the power of the method. David Waxman is a Chinese Government thousand talent Professor at Fudan University, and he has contributed a lot to the field of Theoretical Population Genetics. For more details, please see:http://www.sciencemag.org/content/346/6207/311.8.short