Phylogeography of the striped field mouse, Apodemus agrarius (Rodentia: Muridae), throughout its distribution range in the Palaearctic region

To better understand the evolutionary history of oriental wildlife newcomers in Europe, we studied the phylogeography and
demographic history of the striped field mouse, Apodemus agrarius, throughout its Palaearctic distribution area. Genetic
datasets including cytochrome b gene sequences and microsatellite markers were analysed using a large range of population
genetics methodologies, including coalescent models and approximate Bayesian computations. Our results showed high
mitochondrial genetic homogeneity among A. agrarius populations throughout the Palaearctic region, but microsatellite
markers detected a finer population structure with the genetic differentiation of populations from the Eastern and Western
distribution ranges. The Western colonisation likely originated from Far East Russian populations during one of the last
interglacials. After their colonisation of the Central Asia and Western regions, the Central Palaearctic populations became
isolated from their Eastern relatives. Our coalescent-based approaches suggested a separation between these two distribution
ranges around 38 kya or more recently (around 11 kya). Limited gene flow still happened between populations in the two main
distribution ranges, mainly from the Eastern to Western populations. Our study, for the first time, provides an overview of
the evolutionary and demographic history of the striped field mouse throughout the Palaearctic region. A. agrarius appears
to be an Asiatic immigrant and a relatively new member of the European fauna community. This study further confirms the
important role of Far East Asian regions as a source of European biodiversity.