Data from: Invasion genetics of a human commensal rodent: the black rat Rattus rattus in Madagascar

Studies focusing on geographical genetic patterns of commensal species and
on human history complement each other, and provide proxies to trace
common colonisation events. On Madagascar, the unintentional introduction
and spread of the commensal species Rattus rattus by people may have left
a living clue of human colonization patterns and history. In this study,
we addressed this question by characterising the genetic structure of
natural populations of R. rattus using both microsatellites and
mitochondrial sequences, on an extensive sampling across the island. Such
datasets were analysed by a combination of methods using population
genetics, phylogeography and Approximate Bayesian Computation. Our results
indicated two different introduction events to Madagascar from the same
ancestral source of R. rattus, one in the extreme north of the island and
the other further south. The latter was the source of a large spatial
expansion, which may have initially started from an original point located
on the southern coast. The inferred timing of introduction events –
several centuries ago - is temporally congruent with the Arabian trade
network in the Indian Ocean, which was flourishing from the middle of the
first millennium.