Data from: Global population divergence and admixture of the brown rat (Rattus norvegicus)

Native to China and Mongolia, the brown rat (Rattus norvegicus) now enjoys a worldwide distribution. While black rats and the house mouse tracked the regional development of human agricultural settlements, brown rats did not appear in Europe until the 1500s, suggesting their range expansion was a response to relatively recent increases in global trade. We inferred the global phylogeography of brown rats using 32k SNPs, and detected 13 evolutionary clusters within five expansion routes. One cluster arose following a southward expansion into Southeast Asia. Three additional clusters arose from two independent eastward expansions: one expansion from Russia to the Aleutian Archipelago, and a second to western North America. Rapid westward expansion resulted in the colonization of Europe from which subsequent colonization of Africa, the Americas, and Australasia occurred, and multiple evolutionary clusters were detected. An astonishing degree of fine-grained clustering between and within sampling sites underscored the extent to which urban heterogeneity shaped genetic structure of commensal rodents. Surprisingly, few individuals were recent migrants, suggesting that recruitment into established populations is limited. Understanding the global population structure of R. norvegicus offers novel perspectives on the forces driving the spread of zoonotic disease, and aids in development of rat eradication programs.褐家鼠（Rattus norvegicus）原产于中国与蒙古国，如今已遍布全球。黑鼠与小家鼠曾伴随人类农业聚落的区域性发展而扩散，但褐家鼠直至16世纪才在欧洲出现，这表明其分布范围扩张是对近代全球贸易增长的响应。我们基于32k个单核苷酸多态性（Single Nucleotide Polymorphisms，SNPs）位点，推断了褐家鼠的全球系统地理学特征，并在五条扩散路径中鉴定出13个进化簇。其中一个进化簇源自向南扩散至东南亚的种群分支。另有三个进化簇源自两次独立的向东扩散事件：一次是从俄罗斯向阿留申群岛迁徙，另一次则扩散至北美西部。快速的向西扩散使得褐家鼠成功定殖欧洲，随后又从欧洲进一步扩散至非洲、美洲及澳大拉西亚，在此过程中形成了多个进化簇。采样位点内部及位点间存在极高分辨率的精细聚类结构，这凸显了城市异质性对伴生啮齿类遗传结构的塑造强度。令人意外的是，近期发生迁移的个体极少，这表明已建立种群的种群补充过程较为受限。阐明褐家鼠的全球种群结构，可为驱动人畜共患病传播的相关机制提供全新研究视角，同时也有助于制定啮齿类灭杀防控方案。