| Summary: | 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. Microsatellite data (17 loci) for 38 population samples of Malagasy Rattus rattusL1: title; L2-18: locus names; individual genotypes in a "Genepop" format. Population samples are separated by "pop" and labelled according the 4 first letters of the individual code.Ratmadtotf.txtInput datafile for the main DIYABC analyses of the paper: microsatellite and D-loop data for two Madagascan population samplesL1: title; L2-18: locus names; individual genotypes (Genepop format) for two population samples of Madagascar: DIE (Diego Suarez), north Madagascar, and MAN (Mandena), south of MadagascarDieMan_dloop.txtCode for Diyabc analysesReference table associated with the file DieMan_Dloop.txt and containing the code for scenarios, chosen prior distributions and summary ...
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