How much genetic variation is there?

The two populations do not differ concerning morphology, behaviour and ecology. Analysis of nuclear DNA revealed relatively high genetic variation in the Scandinavian brown bear, even though the poulation has passed through a bottleneck, which usually reduces the genetic variation. (In 1930 the bear was almost exterminated, and there were an estimated 130 individuals in several small isolated areas.)
The high genetic diversity we found was surprising and may be due to the short bottleneck period (in bear generations) and that the survival of some small isolated populations which later come into contact with each other  may have been positive, as different alleles may have been retained in different populations.
We have found males in in the North and the South with southern or northern mtDNA, respectively indicating that interchange occurs between the southern and northern brown bears.  The genetic exchange between the different populations is due to the long dispersal of the male bears in their search for females.