2. Species identification
Defining species identity is a prerequisite for studying regional and interregional adaptation in white oaks, as each species possesses a distinct ecological profile and potential different molecular adaptations. However, for white oaks this is a challenging task as several species can grow on similar site conditions and hybridization between species is possible.
In Central Europe, several genetic marker sets have been established to identify white oak species and to determine its genetic structure. However, for the Eastern Mediterranean region, information on the species’ gene pools is still limited. Hence, ACORN will perform complementary morphological assessments in order to establish sets of molecular markers for species identification in South-Eastern Europe.
Morphological traits are used to identify tree species in the field. However, especially in white oaks, combined with frequent hybridization, visual characteristics might be ambiguous.
Nevertheless, subsequent molecular analysis can be used to identify species, ecotypes, and hybridization.
To extract DNA, tissue of each sample tree has to be collected in the field (e.g. a fresh leave). Then each sample is analysed by using a specific DNA marker set for white oaks. Each DNA marker is corresponding to a polymorhic DNA locus which shows species specific characteristics (specific alleles) and, hence, can be used for species identification.
The left figure shows leafs and acorns of tree different oak trees: (upper left) Q. robur, (upper right) Q. petraea, and (bottom) potential hybrid.
Species identification for all sampled trees (morphological and molecular analysis)
Intraspecific genetic structure
Assignment of the origin of the study populations