Mitochondrial DNA RFLP analysis reveals low levels of genetic variation in European bison Bison bonasus

Originating from only 12 individuals, the extant population of the European bison Bison bonasus (Linnaeus, 1758) has been severely bottlenecked and consequently exhibits a high degree of inbreeding. Previous studies of allozyme variation are to some extent contradictory regarding levels of genetic variation. However, they brought about evidence for a genetic depletion at nuclear loci. In this study, we investigated the mitochondrial DNA (mtDNA) of 26 specimens of European bison from Bialowieza Primeval Forest, Eastern Poland. All of them showed the same mitochondrial haplotype. An evaluation of the analytical power of the applied method showed, that it might be suitable to detect major mitochondrial lineages, though rare haplotypes might be overlooked. The absence of detected genetic variation in the mtDNA is corroborated by a calculation of time until fixation of a single haplotype in European bison during the bottleneck, which might be less than 100 years. In conclusion, the low levels of nuclear and the absence of mitochondrial variation are in concordance with theoretical expectations for species, which have experienced a prolonged population bottleneck.