DNA barcoding is a new approach in comparative genomics of plants

Assessment of phylogenetic inter-relationships in the genus Cymbidium (Orchidaceae) based on internal transcribed spacer region of rDNA

“…Several fragments of the chloroplast genome (trnH-psbA, matK, rpoC, rpoB, and rbcL) in combinations of two or three regions have also been used as candidate regions with highest potential, however, more representative samples should be examined to choose the best candidate in such approach (Shneer, 2009). After comparison of candidate DNA barcodes viz., psbA-trnH, trnH-psbA, matK, rbcL, rpoC1, ycf5, and ITS), it was authentically concluded that ITS sequences (especially ITS 2) of nuclear rRNA genes may be used as potential DNA barcode in highly variable plants for establishment of molecular phylogenetic relationships at species level (Shneer, 2009;Chen et al, 2010). Several studies have shown that these spacer regions can be used for establishment of phylogeny among closely related taxa, identification of species or strains (Hillis and Dixon, 1991) including Cymbidium (Cameron et al, 1999;Van den Berg et al, 2002).…”

Assessment of phylogenetic relationship of rare plant species collected from Saudi Arabia using internal transcribed spacer sequences of nuclear ribosomal DNA

“…Therefore, the ITS1-5.8S-ITS2 region has been extensively used for phylogenetic analyses in plants and animals (Baldwin et al, 1995;Alvarez and Wendel, 2003), establishment of phylogeny between closely related taxa and identification of species or strains (Hillis and Dixon, 1991). The ITS sequences (mainly ITS 2) of nrRNA genes may be used as a potential DNA barcode in highly variable plants for establishment of molecular phylogenetic relationships at the species level (Shneer, 2009;Chen et al, 2010).…”

Review on molecular markers for identification of Orchids

“…Since the last classification of Orchidaceae in 2003, there has been major progress in the determination of relationships, despite that almost all of the problematic placements recognised in the previous classification 11 years ago have now been resolved by molecular methods [9]. However barcoding for the identification of plants, as well as orchid species, still faces many problems and needs improvement.…”

“…The single region 5' end of cytochrome c-oxidase 1 (CO1) from the mitochondrial genome is quite successfully used for the identification of animals [8,9]. However searching for DNA barcode in plants is far more challenging than in animals.…”

“…Besides that, they exist in cells with high numbers of copies [5,9]. The flanked regions 5.8S at the middle and 18S, 26S at the two ends of the ITS fragment, are conserved sequences which are useful to develop primers [9] (Fig. 1).…”