The distribution of genetic variation in Norway spruce (Picea abies Karst.) populations of the Western Alps

Aim In order to look for a possible centre of survival for the Norway spruce (Picea abies Karst.) in the south-western Alps, six natural populations of this area were investigated by means of genetic markers in order to assess the degree and the distribution of genetic diversity within the species. Location Western and South-western Alps. Methods Populations were genotyped using seven simple sequence repeat (SSR) markers. Basic population genetics parameters were estimated and the amount of genetic differentiation calculated. Results A large amount of variability was found (0.59 < H, < 0.67); genetic differentiation as measured by F-ST, was 0.05, close to other similar studies; no isolation by distance was detected by a Mantel test. Analysis of molecular variance confirmed a high degree of variability within populations and a low degree of variability among populations. Finally, the number of populations from which those observed could have arisen was estimated by Bayesian analysis. Main conclusions The results presented here suggest that the present populations derive their genetic make-up from three inferred clusters. The possible existence in this area of a relict/refuge population during the last glaciation is discussed.