Population genetic structure of the endangered freshwater crayfish Austropotamobius pallipes, assessed using RAPD markers

Random amplified polymorphic DNA (RAPD) analysis was performed to character ize the genetic diversity of Austropotamobius pallipes, a threatened freshw ater crayfish native to Europe. Four decamer primers which generated six un ambiguous polymorphic bands were used to analyse crayfish from 21 populatio ns sampled in the major part of its range. Genetic diversity within populat ions of A. pallipes, estimated by Shannon's diversity index, ranged from 0 to 0.446 with a mean or 0.159. A UPGMA dendrogram constructed from pairwise (DST values between Populations, revealed three clusters corresponding to populations sampled in the southern, northwestern and eastern part or its r ange. AMOVA analysis revealed a high genetic structure of A. pallipes popul ations Phi (ST) = 0.814, with 73.11% of the genetic variation distributed b etween these clusters. It suggests it historical geographical separation of these groups into three refugial areas, probably in the Rhine, Mediterrane an and Atlantic basins during recent glaciations. The close genetic relatio nships between English and western French populations are in accordance wit h a natural postglacial origin of English Populations from individuals havi ng survived in an Atlantic refugium. However, the present results suggest t hat the Irish stock originated from a human translocation of individuals fr om an Atlantic refugium.