The genetic structure of Scandinavian Willow Ptarmigan (Lagopus lagopus lagopus) populations

Temporal (between years) and spatial (between populations) variation in gene frequencies and heterozygosity was studied in 8 polymorphic serum esterase loci in 602 Willow Ptarmigan (Lagopus lagopus lagopus) from Scandinavian localities during four years. Most of the gene diversity (97 %) was found within years from the same population. Of the remaining variation, about twice as much was attributed to temporal as to spatial differences. About the same genetic distance (D, NEI1975) was observed between populations (0.0082) as that between years from the same population (0.0074). The gene frequencies within each population varied significantly between years, average heterozygosity did not. A significantly different heterozygosity was recorded in all but two pairwise comparisons between populations. Since there was little variation in heterozygosity between years compared to the variation between populations, we suggest that average heterozygosity reflects adaption to local environmental conditions in Willow Ptarmigan.