Genetic variation of Cerastium alpinum L. from Babia Gora, a critically endangered species in Poland

Babia Gora massif is the only site of occurrence of the Cerastium alpinum L. in Poland, an arctic-alpine perennial plant with a wide distribution in North America, northwestern Asia, and Europe. To determine whether the isolated Polish populations are genetically distinct, we have performed an evaluation of C. alpinum from Babia Gora with the use of iPBS markers. A total number of 133 individuals of C. alpinum from seven populations representing four localizations of the species were analyzed, i.e., from Babia Gora (Poland), Alps (Switzerland), Nuolja massif (Sweden), and Kaffioyra (Svalbard, Norway). Genetic analysis of all C. alpinum samples using eight PBS primers identified 262 bands, 79.4% of which were polymorphic. iPBS markers revealed low genetic diversity (average H-e = 0.085) and high population differentiation (F-ST = 0.617). AMOVA results confirmed that the majority of the genetic variation (62%) was recorded among populations. The grouping revealed by PCoA showed that C. alpinum from Svalbard is the most diverged population, C. alpinum from Switzerland and Sweden form a pair of similar populations, whereas C. alpinum from the Babia Gora form a heterogeneous group of four populations. Results of isolation by distance analysis suggested that the spatial distance is the most probable cause of the observed differentiation among populations. Although significant traces of a bottleneck effect were noted for all populations of C. alpinum from Babia Gora, the populations still maintain a low but significant level of genetic polymorphism. These results are of great importance for developing conservation strategies for this species in Poland.