Migration is a process with important implications for the genetic structure of populations. However, there is an aspect of migration seldom investigated in plants: migration between temporally isolated groups of individuals within the same geographic population. The genetic implications of temporal migration can be particularly relevant for semelparous organisms, which are those that reproduce only once in a lifetime after a certain period of growth. In this case, reproductive asynchrony in individuals of the same population generates demes of individuals differing in their developmental stage (non-reproductive and reproductive). These demes are connected by temporal migrants, that is, individuals that become annually asynchronous with respect to the rest of individuals of their same deme. Here, we investigated the extent of temporal migration and its effects on temporal genetic structure in the biennial plant Erysimum mediohispanicum. To this end, we conducted two independent complementary approaches. First, we empirically estimated temporal migration rates and temporal genetic structure in four populations of E. mediohispanicum during three consecutive years using nuclear microsatellites markers. Second, we developed a demographic genetic simulation model to assess genetic structure for different migration scenarios differing in temporal migration rates and their occurrence probabilities. We hypothesized that genetic structure decreased with increasing temporal migration rates due to the homogenizing effect of migration. Empirical and modelling results were consistent and indicated a U-shape relationship between genetic structure and temporal migration rates. Overall, they indicated the existence of temporal genetic structure and that such genetic structure indeed decreased with increasing temporal migration rates. However, genetic structure increased again at high temporal migration rates. The results shed light into the effects of reproductive asynchrony on important population genetic parameters. Our study contributes to unravel the complexity of some processes that may account for genetic diversity and genetic structure of natural populations.

中文翻译：

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时间迁移率影响具有生殖异步性的两年生 Erysimum mediohispanicum 种群的遗传结构。

迁移是一个对种群遗传结构具有重要影响的过程。然而，在植物中很少研究迁移的一个方面：同一地理种群内时间隔离的个体群体之间的迁移。时间迁移的遗传影响可能与半生生物特别相关，半生生物是在一定时期生长后一生仅繁殖一次的生物。在这种情况下，同一种群个体的生殖不同步会产生不同发育阶段（非生殖和生殖）的个体。这些领地由时间迁移者连接，也就是说，个体每年都与同一领地的其他人不同步。这里，菊苣。为此，我们进行了两种独立的互补方法。首先，我们凭经验估计了四个E. mediohispanicum种群的时间迁移率和时间遗传结构连续三年使用核微卫星标记。其次，我们开发了一个人口遗传模拟模型来评估不同迁移场景的遗传结构，这些场景在时间迁移率及其发生概率方面存在差异。我们假设由于迁移的同质化效应，遗传结构随着时间迁移率的增加而减少。经验和建模结果一致，表明遗传结构和时间迁移率之间存在 U 形关系。总体而言，他们表明时间遗传结构的存在，并且这种遗传结构确实随着时间迁移率的增加而减少。然而，遗传结构在高时间迁移率下再次增加。结果揭示了生殖不同步对重要种群遗传参数的影响。我们的研究有助于解开一些可能解释自然种群遗传多样性和遗传结构的过程的复杂性。