Molecular variation within and between ten populations of Primula farinosa (Primulaceae) along an altitudinal gradient in the northern Alps

Abstract

Summary Factors affecting gene flow within and between populations, such as landscape topography, vegetation structure or phenology change drastically with increasing altitude. Genetic differentiation between populations and different levels of genetic diversity within populations from different altitudes may, therefore, be expected. In a random amplified polymorphic DNA (RAPD) analysis of ten populations of Primula farinosa along an altitudinal gradient 96 fragments could be amplified of which 82.3% were polymorphic. An analysis of molecular variance (AMOVA) revealed 20.59% of the genetic variation between and 79.41% within populations. 8.47% of the molecular variance were found among two altitudinal groups above and beneath 1750 m. An UPGMA cluster analysis based on Nei's genetic distances between populations using the RAPD data corroborated the results of the AMOVA and showed two distinct groups of populations above +and beneath 1750 m. Genetic diversity within populations measured as Nei's gene diversity and Shannon's information index ranged from 0.12 to 0.18 and 0.18 to 0.26, respectively. Genetic diversity was higher at the higher altitudes for the eight unused populations. Upper populations were, therefore, genetically more diverse than lower populations. Genetic differentiation between upper and lower populations and higher diversity of upper populations are ascribed to different flowering times of upper and lower populations and to the gradual retreat of the forest, which hampers the exchange of seeds and pollen between upper and lower populations but also between lower populations.