Drastic bottlenecks in the endangered crayfish species Austropotamobius pallipes in Spain and implications for its colonization history.

Variation in mitochondrial DNA (mtDNA) was surveyed, using restriction endonucleases, in the white-clawed crayfish, Austropotamobius pallipes lusitanicus, from 14 populations sampled in Spain. Four additional samples from France (1), Slovenia (1) and Italy (2) were also analysed. Among the 11 haplotypes listed, only one was detected from the 154 animals sampled from Spanish populations. This haplotype was also recorded in the Fosso di Ferfereta population (Italy). Estimates of nucleotide sequence divergence among haplotypes ranged from 0.45% to 17.4%. Interpopulational genetic relationships showed that Spanish populations were closely related to those of Fosso di Ferfereta with a small genetic distance (0.0003) found between them. AMOVA revealed that most of the genetic variance (71.97%) was attributed to variation between European regions. These results are in accordance with a drastic bottleneck event during the history of the Spanish populations. Four suggestions, based on human introduction, selection and recent or ancient historical events are discussed in relation to the lack of genetic variation in the Spanish crayfish stock.