Gavrilets Sergey, Michalakis Yannis
Department of Ecology, University of Tennessee, Knoxville, Tennessee 37996, USA.
Evolution. 2008 Dec;62(12):3100-16. doi: 10.1111/j.1558-5646.2008.00513.x. Epub 2008 Sep 11.
We study victim-exploiter coevolution in a spatially heterogeneous island model. In each species, fitness consequences of between-species interactions are controlled by a single haploid diallelic locus. Our emphasis is on the conditions for the maintenance of genetic variation, the dynamic patterns observed, the extent of local adaptation and genetic differentiation between different demes, and on how different parameters (such as the strength and heterogeneity in selection, migration rates, and the number of sites) affect the dynamic and static behavior of the system. We show that under spatially homogeneous selection the maintenance of genetic variation is possible through asynchronous nonlinear dynamics where the allele frequencies in a majority of demes quickly synchronize but the rest do not. Spatially heterogeneous selection can maintain genetic variation even if migration rates are maximal. This happens in an oscillatory way. Genetic variation is most likely to be maintained at high levels if the heterogeneity in selection is large. If there are some restrictions on migration, genetic variation can be maintained at a stable equilibrium. This behavior is most likely at intermediate migration rates. In this case, the system can exhibit high spatial subdivision as measured by F(ST) values but relatively low local adaptation.
我们在空间异质性岛屿模型中研究受害者 - 剥削者的协同进化。在每个物种中，物种间相互作用的适合度后果由单个单倍体双等位基因位点控制。我们重点关注遗传变异维持的条件、观察到的动态模式、局部适应程度以及不同deme之间的遗传分化，以及不同参数（如选择的强度和异质性、迁移率和位点数量）如何影响系统的动态和静态行为。我们表明，在空间均匀选择下，通过异步非线性动力学有可能维持遗传变异，其中大多数deme中的等位基因频率会迅速同步，但其余的不会。即使迁移率最大，空间异质性选择也能维持遗传变异。这以振荡方式发生。如果选择的异质性很大，遗传变异最有可能在高水平上维持。如果对迁移有一些限制，遗传变异可以在稳定平衡中维持。这种行为最有可能在中等迁移率时出现。在这种情况下，通过F(ST)值衡量，系统可以表现出高度的空间细分，但局部适应相对较低。
