Mitochondrial DNA variation in the European otter (Lutra lutra) and the use of spatial autocorrelation analysis in conservation

To add genetic information to the international conservation efforts on European otters Lutra lutra, we investigated the genetic population structure in and around a known "source" population of the otter, the Oberlausitz (OL) in eastern Germany. This was complemented by a first survey of genetic variation levels in the Central European otter population. Sequence analysis of 300bp of the mitochondrial control region in 76 specimens from the eastern German study region and 53 individuals from several other European populations revealed a low level of genetic variation, with only 5 haplotypes present and nucleotide diversities within populations ranging from 0.00% to 0.17%. Apart from eastern Germany, one haplotype was by far the most abundant one, from which other, only locally occurring types, could be derived by a single point mutation. This suggests a single Pleistocene refugium from which the analyzed European regions have been reinvaded after the glaciations. Within eastern Germany, two abundant haplotypes were found. Their occurrence differed significantly among subregions of eastern Germany. The uneven distribution of a locally restricted but abundant haplotype could be explained by isolation-by-distance and might reflect emigration from the OL source population to surrounding regions. This suggests that vital local populations can indeed serve as "sources" for the invasion of surrounding areas. Given a suitable genetic marker, we suggest a spatial autocorrelation analysis to monitor the genetic effect of such an emigration from a source population.