Department of Physics, Harvard University, Cambridge, MA 02138;
Department of Physics, University of Rome Tor Vergata, 00133 Rome, Italy.
Proc Natl Acad Sci U S A. 2019 Jan 8;116(2):373-378. doi: 10.1073/pnas.1812829116. Epub 2018 Dec 26.
Competition between biological species in marine environments is affected by the motion of the surrounding fluid. An effective 2D compressibility can arise, for example, from the convergence and divergence of water masses at the depth at which passively traveling photosynthetic organisms are restricted to live. In this report, we seek to quantitatively study genetics under flow. To this end, we couple an off-lattice agent-based simulation of two populations in 1D to a weakly compressible velocity field-first a sine wave and then a shell model of turbulence. We find for both cases that even in a regime where the overall population structure is approximately unaltered, the flow can significantly diminish the effect of a selective advantage on fixation probabilities. We understand this effect in terms of the enhanced survival of organisms born at sources in the flow and the influence of Fisher genetic waves.
海洋环境中生物物种间的竞争受到周围流体运动的影响。例如，当被动迁徙的光合生物被限制在一定深度生存时，水体的汇聚和发散会产生有效的二维可压缩性。在本报告中，我们试图对流动条件下的遗传学进行定量研究。为此，我们将一维两种群的无格元基于主体的模拟与弱可压缩速度场相结合——首先是正弦波，然后是湍流的壳模型。我们发现，对于这两种情况，即使在总体种群结构大致不变的情况下，流动也会显著降低选择优势对固定概率的影响。我们根据出生在流源的生物的存活率提高和费希尔遗传波的影响来理解这种效应。
