[en] Black rat ; Islands ; karyotype ; mtDNA ; Rattus rattus ; Western Europe
[en] The colonisation of Europe by the black rat (Rattus rattus) dates back only to the Roman times. This rodent is now widespread all over the continent as well as on many islands where it was introduced by man. In some instances, insular populations are morphologically differentiated by their greater size. In order to study the possible origin of these insular populations, rats were caught on many Mediterranean (Sicily, Sardinia, Lavezzi, Corsica, Elba, Porquerolles) and Atlantic islands (Ré, Oléron, Azores) and compared to animals from continental Europe (Spain), and Africa (Tunisia, Benin). Their karyotype was determined and their mtDNA restriction patterns studied using the HAE III and RSA I endonucleases and a polyacrylamide gel electrophoresis. These patterns appear very similar to each other though one of them is specific to the African animals, probably indicating that Europe and Africa were colonised by different strains.