Comparative phylogeography of two commensal rat species (Rattus tanezumi and R. norvegicus) in China: Insights from mitochondiral DNA, microsatellite and RADseq

<p><em><span>Rattus norvegicus</span></em><span> and </span><em><span>Rattus tanezumi</span></em><span> are dominant species of Chinese house rats, but the colonization and demographic history of two species in China have not been thoroughly explored.</span><span> Phylogenetic analyses with mitochondrial DNA including 486 individuals from 31 localities revealed that </span><span><em>R</em>. <em>norvegicus</em></span><span> is widely distributed in China, </span><span>R. <em>tanezumi</em></span><span> is mainly distributed in southern China with currently invading northward; northeast China was the natal region of </span><span><em>R</em>. <em>norvegicus</em></span><span>, while the spread of </span><span><em>R</em>. <em>tanezumi</em></span><span> in China most likely started from the southeast coast. A total of 123 individuals from 18 localities were subjected to 2b‐RAD analyses. In the neighbor‐joining tree, individuals of </span><span><em>R</em>. <em>tanezumi</em></span><span> grouped into geographic‐specific branches, and populations from the southeast coast were ancestral groups, which confirmed the colonization route from the southeast coast to central and western China. However, individuals of </span><span><em>R</em>. <em>norvegicus</em></span><span> were generally grouped into two clusters instead of geographic‐specific branches. One cluster comprised inland populations, and another cluster included both southeast coast and inland populations, which indicated that the spread history of </span><span><em>R</em>. <em>norvegicus</em></span><span> in China was complex; in addition to on‐land colonization, shipping transportation also played a great role. ADMIXTURE and principal component analyses provided further supports for the colonization history. Demographic analyses revealed that climate changes at ~40,000 to 18,000 years ago and ~4000 years ago had led to population declines of both species; the </span><span>R<em>.</em> <em>norvegicus</em></span><span> declined rapidly while the population of </span><span><em>R</em>. <em>tanezumi</em></span><span> continuously expanded since ~1500 years ago, indicating the importance of interspecies' competition in their population size changes. Our study provided a valuable framework for further investigation of phylogeography of two species in China.</span></p>