New molecular data favour an anthropogenic introduction of the wood mouse (Apodemus sylvaticus) in North Africa

According to fossil data the wood mouse arrived in North Africa 7,500 ya,
while it was present in Europe since early Pleistocene. Previous molecular
studies suggested that its introduction in North Africa probably occurred via
the Strait of Gibraltar more than 0.4 Mya ago. In this study, we widely
sampled wood mice in order to get a better understanding of the
geographic and demographic history of this species in North Africa, and
possibly to help resolving the discrepancy between genetic and
paleontological data. Specifically we wanted to answer the following
questions: (1) when and how did the wood mouse arrive in North Africa?
and (2) What is its demographic and geographic history in North Africa
since its colonization? We collected in the field 438 new individuals and
used both mtDNA and six microsatellite markers to answer these
questions. Our results confirm that North African wood mice have a
southwestern European origin and colonized the Maghreb through the
Gibraltar strait probably during the Mesolithic or slightly after. They first
colonized the Tingitane peninsula and then expanded throughout North
Africa. Our genetic data suggest that the ancestral population size
comprised numerous individuals reinforcing the idea that wood mice did
not colonize Morocco accidentally through rafting of a few individuals, but
via recurrent/multiple anthropogenic translocations. No spatial structuring
of the genetic variability was recorded in North Africa, from Morocco to
Tunisia.