Abstract
The purpose of the current study was to determine the phylogenetic relationships between the Arabis alpina L. growing naturally in Afro-Alpina Mountains at south western regions of the Kingdom of Saudi Arabia (KSA) and its closely related species. A case study approach was applied to DNA barcode, secondary internal transcribed spacer (ITS2), chloroplast maturase-K (matK), ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL) for the identification and determination phylogenetic relationship. An analysis of barcode data was conducted using the basic local alignment search tool (BLAST), pairwise genetic distances and the maximum likelihood (ML) methods. The results showed the clear superiority of the nuclear ITS2 loci and chloroplast matK gene with a 100% success rate found for DNA amplification, sequencing, and 100% species resolution. A maximum likelihood ML tree of ITS2 and matK strongly supported the presence of variations between A. alpina of Saudi Arabia and specimens of A. alpina of different geographical origins. This study represented the first inspection to A. alpina in KSA, and is useful in species identification, conservation and evolutionary studies. More studies are needed to verify if the A. Alpina of the KSA can be considered a subspecies.