Genetic variation in the liverwort Bazzania trilobata inferred from ISSR markers

Abstract

The distribution of Bazzania trilobata in Poland coincides with two parts of the natural distribution range of Norway spruce: the mountains of southern Poland and the northeastern lowlands. The occurrence of this species is connected with primeval forest communities and it was recognized as a relict of them. Genetic variation of 10 populations of B. trilobata from two different regions of Poland (lowlands and mountains) was studied in order to establish the genetic structure of this species and to compare the level of genetic variation within and among populations originating from primeval and managed forests. An analysis based on polymorphic inter-simple sequence repeat (ISSR) loci revealed a high level of total gene diversity in B. trilobata (HT=0.308). A higher amount of polymorphism was found among than within populations. Genetic variation of populations from the primary forest (Tatras and Białowieza National Park) was higher than for those originating from disturbed habitats. The Bayesian method showed consistent grouping of samples corresponding with populations, with the best grouping in 12 different clusters reflecting a geographic pattern. The geographic pattern of genetic differentiation was supported by a neighbour-joining (NJ) dendrogram based on genetic distances. All mountain populations were grouped together in one subcluster, but lowland populations were more differentiated and did not form one clear group.