The genetic swamping hypothesis proposes that gene flow from central to peripheral populations inhibits local adaptation and is one of the most widely recognized explanations for range limitation. We evaluated empirical support for this hypothesis in studies quantifying patterns of gene flow to peripheral populations and their resulting fitness outcomes. We found little evidence that gene flow is generally asymmetric from central to peripheral populations and also that gene flow tends to have positive effects on edge population fitness. These findings contravene the long-held assumption that genetic swamping is a common driver of species range limits, and bear important implications for understanding the role of gene flow in range evolution and for predicting and managing eco-evolutionary responses to climate change.

遗传沼泽假说提出，从中心种群到外围种群的基因流动会抑制局部适应，这是对范围限制的最广为人知的解释之一。我们在量化基因流向周围人群的模式及其产生的适应性结果的研究中，评估了该假设的经验支持。我们发现几乎没有证据表明基因流从中心人群到外围人群总体上是不对称的，而且基因流倾向于对边缘人群适应性产生积极影响。这些发现违背了一个长期以来的假设，即遗传沼泽是物种范围限制的常见驱动因素，并且对于理解基因流在范围演变中的作用以及预测和管理对气候变化的生态进化响应具有重要意义。