Population genetics of White-clawed Crayfish
The White-clawed Crayfish Austropotamobius pallipes is one of the largest and most charismatic freshwater invertebrates in Europe, as well as one of the most threatened. There is a long history of exploitation of this species for food.
Research by a team at the University of Poitiers asked whether this history has affected the current distribution and population biology of the species. They compared the crayfish with the Brown Trout, Salmo trutta, another freshwater species with a similar ecology, whose colonisation of Europe after the Ice Age was not assisted by human activity. In both the crayfish and the trout, genetic structure reflects each subpopulation’s nearest glacial refugia, from which they originated. The high genetic isolation (FST = 0.22) of French subpopulations suggests that there is no dispersal of individuals between river basins; those that are also highly inbred (with heterozygosity of or near 0) are therefore highly vulnerable to local extinction.
One surprising result was that the whole population of Ireland has very low genetic diversity, as it originates from a single introduction from Western France – most likely the Poitou-Charentes region. Similarly, the Spanish population was introduced from Tuscany in Italy, most likely by the Romans.
by Josh Nightingale and Juan Rodríguez