Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA.
School for Environment and Sustainability, University of Michigan, Ann Arbor, MI 48109, USA.
Biol Lett. 2021 Apr;17(4):20200901. doi: 10.1098/rsbl.2020.0901. Epub 2021 Apr 14.
Understanding how genetic variation is maintained in a metapopulation is a longstanding problem in evolutionary biology. Historical resurveys of polymorphisms have offered efficient insights about evolutionary mechanisms, but are often conducted on single, large populations, neglecting the more comprehensive view afforded by considering all populations in a metapopulation. Here, we resurveyed a metapopulation of spotted salamanders () to understand the evolutionary drivers of frequency variation in an egg mass colour polymorphism. We found that this metapopulation was demographically, phenotypically and environmentally stable over the last three decades. However, further analysis revealed evidence for two modes of evolution in this metapopulation-genetic drift and balancing selection. Although we cannot identify the balancing mechanism from these data, our findings present a clear view of contemporary evolution in colour morph frequency and demonstrate the importance of metapopulation-scale studies for capturing a broad range of evolutionary dynamics.
理解遗传变异在复合种群中是如何维持的，是进化生物学中长期存在的问题。对多态性的历史研究为进化机制提供了有效的见解，但通常是在单个大种群上进行的，而忽略了通过考虑复合种群中的所有种群来提供更全面的观点。在这里，我们对斑点蝾螈（）的复合种群进行了重新调查，以了解卵群颜色多态性频率变化的进化驱动因素。我们发现，在过去的三十年里，这个复合种群在人口统计学、表型和环境方面都很稳定。然而，进一步的分析显示，这个复合种群中存在两种进化模式——遗传漂变和平衡选择。尽管我们无法从这些数据中确定平衡机制，但我们的发现清楚地展示了当代颜色形态频率进化的情况，并证明了在复合种群尺度上进行研究对于捕捉广泛的进化动态的重要性。
