Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland.
Genetics. 2013 Mar;193(3):953-71. doi: 10.1534/genetics.112.147785. Epub 2013 Jan 10.
Genetic diversity is essential for population survival and adaptation to changing environments. Demographic processes (e.g., bottleneck and expansion) and spatial structure (e.g., migration, number, and size of populations) are known to shape the patterns of the genetic diversity of populations. However, the impact of temporal changes in migration on genetic diversity has seldom been considered, although such events might be the norm. Indeed, during the millions of years of a species' lifetime, repeated isolation and reconnection of populations occur. Geological and climatic events alternately isolate and reconnect habitats. We analytically document the dynamics of genetic diversity after an abrupt change in migration given the mutation rate and the number and sizes of the populations. We demonstrate that during transient dynamics, genetic diversity can reach unexpectedly high values that can be maintained over thousands of generations. We discuss the consequences of such processes for the evolution of species based on standing genetic variation and how they can affect the reconstruction of a population's demographic and evolutionary history from genetic data. Our results also provide guidelines for the use of genetic data for the conservation of natural populations.
遗传多样性对于种群的生存和适应不断变化的环境至关重要。人口过程（例如瓶颈和扩张）和空间结构（例如迁移、种群数量和大小）已知会影响种群遗传多样性的模式。然而，尽管这种事件可能很常见，但很少有人考虑迁移的时间变化对遗传多样性的影响。事实上，在一个物种的数百万年生命周期中，种群的反复隔离和重新连接是常态。地质和气候事件交替隔离和重新连接栖息地。我们在给定突变率和种群数量和大小的情况下，分析记录了迁移突然变化后的遗传多样性动态。我们证明，在瞬态动力学中，遗传多样性可以达到出乎意料的高值，并且可以维持数千代。我们根据遗传变异讨论了这些过程对物种进化的影响，以及它们如何影响从遗传数据重建种群的人口和进化历史。我们的研究结果还为利用遗传数据保护自然种群提供了指导方针。
