Taxonomic position and origin of the endemic Sicilian fir Abies nebrodensis (Lojac.) Mattei based on allozyme analysis

The final publication is availabe at/O documento está disponível em http://www.tuzvo.sk/files/fg/volumes/2001/FG08-2_119-127.pdfAbies nebrodensis (Lojac.) Mattei (Sicilian fir) is a forest tree species endemic to the mountainous regions of northern Sicily (the Madonie Range) that is currently represented by just one population of 29 individuals. The major questions relating to this species are its unknown origin and its uncertain taxonomic position. According to many authors A. nebrodensis is morphologically intermediate between the neighboring Mediterranean Abies species: Abies alba (Mill.) (silver fir), Abies numidica (De Lann) (Algerian fir) and Abies cephalonica (Loud) (Greek fir). In the present study we analyzed eight enzyme systems in the population of A. nebrodensis and in seven populations from A. alba, A. cephalonica and A. numidica. The aim was to clarify the taxonomic position and origin of A. nebrodensis. High values of expected heterozygosity and number of polymorphic loci were found in A. cephalonica, while A. alba and A. nebrodensis showed intermediate levels of polymorphism and A. numidica was the least variable species. All values were similar to those found in other conifers. The relatively high level of diversity found in A. nebrodensis confirms that despite the extremely small population size, the few individuals left in this species still retain a considerable amount of the original genetic variation at the nuclear level. Results also showed that all the species were differentiated from each other, although A. nebrodensis showed a closer affinity to A. alba and in particular to the population from southern Italy. Our results, together with results from previous studies provide support for the classification of A. nebrodensis as a separate taxon and suggest that this species may have originated through a past hybridization event