Microsatellite markers to identify specific alleles in DNA extracted from monovarietal virgin olive oils

The suitability of DNA present in olive oil for PCR analysis has been reported by several authors. However, low concentration, degradation, and the possible presence of additional alleles due to paternal contribution in oils extracted from entire drupes, should be taken into consideration when comparing the amplification profiles of leaves with the corresponding oils for varietal traceability purposes. The aim of this work was to assess, by capillary electrophoresis of microsatellite markers, the phenetic relationships among seven certified Olea europaea L. cultivars, and to verify the genomic equality between leaf DNA and the corresponding monovarietal oil DNA. Moreover, the aim was to establish an identification key to distinguish all the types of oil among them with the minimum number of markers. The results referred to oil DNA, obtained in 70 PCR experiments, confirmed the possibility, in 85.7% of cases, of extracting DNA suitable for the analysis of microsatellites. Ninety percent of the successful amplifications led to identical patterns for leaves and oil DNA. Cima di Melfi shared only 20% of the alleles with the other cultivars. Toscanina and Leccino, showed the highest similarity (about 60%). A single microsatellite was able to distinguish the seven types of oil.