Assessing molecular diversity among 87 species of the Quercus L. genus by RAPD markers

Abstract

Oaks (Quercus sp.) are among the most ecologically and economically important woody Angiosperms of the northern hemisphere. Nowadays, the reduction of Quercus biodiversity is becoming a matter of global concern, and several oak species have been included in the IUCN Red List of Threatened Species. Consequently, characterization and preservation strategies for the oak germplasm are largely promoted. Thus, in this work, the genetic diversity existing among 87 different Quercus species was assessed using the RAPD markers, in order to better typify these specimens, to show the amazing DNA variability of this plant genus, and to confirm or infer new putative molecular correlations. Our data were discussed taking into consideration the phylogenetic and phylogeographic relationships previously proposed by the literature. In general, the obtained results corroborated that the evolutionary pattern of Quercus genus has been extremely intricate and continues to change rapidly, making it difficult to be fully resolved. The evidence collected in the present investigation would confirm the complex evolution of the oaks, due to their high migration capacity, divergence rate, and hybridization propensity. This research, performed on a so large series of species, represents a positive contribution for highlighting the genetic diversity within collections of Quercus germplasm and favouring ex-situ conservation programmes.