Molecular Genetic Assessment of Selected Thyme Species in Palestine Using Random Amplified Polymorphic DNA (RAPD

Traditionally, subjective methods based on the morphological features such as shape, color, texture, and odor are used for the discrimination of herbal medicines. However, these methods fail to provide an accurate for discrimination and authentication. The use of highly discriminatory methods for the identification and characterization of genotypes is essential for plant production and their appropriate use. The RAPD (Random amplified polymorphic DNA) method was used for the genetic fingerprinting of five Palestinian thymes: Thymus syriacus, Thymus fruticosus, Thymus incanus, Thymus majorana, and Thymus capitatus. Among the polymerase chain reaction (PCR)-based molecular techniques, random amplified polymorphic DNA (RAPD) is convenient in performance and does not require any information about the DNA sequence to be amplified. Due to its procedural simplicity, RAPD was used as molecular markers for taxonomic and systematic analyses of plants. After DNA extraction from thyme species, ten decamer primers were tested for their ability to amplify DNA from selected thyme species using RAPD-PCR. The RAPD-PCR products were separated by gel electrophoresis, and then the data were analyzed. Eight of these primers were found to produce fragments for the studied plant species (OPD-19, OPH-02, OPAN-08, PH-01, KFP-6, OPAE-07, OPJ-06 and OPG-66). Three of these primer (OPD-19, OPH-02 and OPAN-08) were polymorphic and generated 78.6% average polymorphism across five Thyme species. The primer OPD-19, and OPH-02 was capable of differentiating thyme species from each other. Pairwise similarity of banding pattern between the studied plant species ranged from 0.18 to 0.67 for the three primers (OPD-19, OPH-02, and OPAN-08). In this study, genetic diversity of five Palestinian Thyme species was revealed successfully using RAPD markers that could be useful in Thyme-breeding programs Palestine. Also these markers could assist in the identification of components in herbal medicine complexes leading to significant improvement in quality control.