Epps Clinton W, Keyghobadi Nusha
Oregon State University, Nash Hall Room 104, Corvallis, OR, 97331, USA.
Department of Biology, Western University, London, ON, N6A 5B7, Canada.
Mol Ecol. 2015 Dec;24(24):6021-40. doi: 10.1111/mec.13454. Epub 2015 Dec 7.
Landscape genetics seeks to determine the effect of landscape features on gene flow and genetic structure. Often, such analyses are intended to inform conservation and management. However, depending on the many factors that influence the time to reach equilibrium, genetic structure may more strongly represent past rather than contemporary landscapes. This well-known lag between current demographic processes and population genetic structure often makes it challenging to interpret how contemporary landscapes and anthropogenic activity shape gene flow. Here, we review the theoretical framework for factors that influence time lags, summarize approaches to address this temporal disconnect in landscape genetic studies, and evaluate ways to make inferences about landscape change and its effects on species using genetic data alone or in combination with other data. Those approaches include comparing correlation of genetic structure with historical versus contemporary landscapes, using molecular markers with different rates of evolution, contrasting metrics of genetic structure and gene flow that reflect population genetic processes operating at different temporal scales, comparing historical and contemporary samples, combining genetic data with contemporary estimates of species distribution or movement, and controlling for phylogeographic history. We recommend using simulated data sets to explore time lags in genetic structure, and argue that time lags should be explicitly considered both when designing and interpreting landscape genetic studies. We conclude that the time lag problem can be exploited to strengthen inferences about recent landscape changes and to establish conservation baselines, particularly when genetic data are combined with other data.
景观遗传学旨在确定景观特征对基因流和遗传结构的影响。通常，此类分析旨在为保护和管理提供信息。然而，由于影响达到平衡时间的因素众多，遗传结构可能更强烈地反映过去而非当代的景观。当前人口过程与种群遗传结构之间这种众所周知的滞后现象，常常使得解读当代景观和人类活动如何塑造基因流变得具有挑战性。在此，我们回顾影响时间滞后因素的理论框架，总结在景观遗传学研究中解决这种时间脱节问题的方法，并评估仅使用遗传数据或结合其他数据来推断景观变化及其对物种影响的方式。这些方法包括比较遗传结构与历史景观和当代景观的相关性、使用具有不同进化速率的分子标记、对比反映在不同时间尺度上运行的种群遗传过程的遗传结构和基因流指标、比较历史样本和当代样本、将遗传数据与物种分布或移动的当代估计相结合，以及控制系统发育地理历史。我们建议使用模拟数据集来探索遗传结构中的时间滞后，并认为在设计和解读景观遗传学研究时都应明确考虑时间滞后。我们得出结论，时间滞后问题可被利用来加强对近期景观变化的推断并建立保护基线，特别是当遗传数据与其他数据结合时。
