Genetic differentiation of foxes (Vulpes vulpes) analysed by means of craniometry and isozymes

In 1997–1999, 411 red foxes Vulpes vulpes were collected from all over Denmark. Among these 205 were used for a univariate craniometrical investigation on six skull traits. 308 of the foxes were analysed by horizontal starch gel electrophoresis. Of the studied 18 enzymes, 14 were monomorphic and four polymorphic. Of the latter ones three were used for further analysis, as one enzyme system was difficult to score. No genetic heterogeneity within samples between sexes was revealed. However both genetic and morphometrical differentiation were found between the regions, with the foxes from Copenhagen significantly deviating from all other samples, including those from the remaining part of Zealand. Thus, our data suggest that the foxes from Copenhagen may be considered as an isolated population with limited amount of gene flow with the other populations in Denmark. Possible causes of such limited gene flow are discussed.