Evaluation of three candidate DNA barcoding loci in Ficus (Moraceae) of the Philippines.

Abstract

DNA barcoding is a technique that produces a quick and reliable species–level identification between closely related and highly diverse species among all forms of life by making use of short DNA sequences from standardized genome sites. Ficus, as having diverse morphology and habit as well as economic, ecological, and pharmaceutical importance is a very good plant subject where DNA barcoding can be applied. In this study, where six indigenous Ficus species were used, the appropriateness of three candidate barcoding loci rbcL, trnH-psbA, and ITS to barcode Philippine endemic Ficus was assessed in terms of these criteria: universality, discriminatory power, and resolution of species. Results reveal that both trnH-psbA and ITS got 100% PCR success rate and 67% sequencing success score, whereas rbcL got 67% PCR success score but 100% sequencing success score. trnH-psbA performed best in terms of discriminatory power, having the highest variable informative site (71.37%), highest mean interspecific distance (0.483225 ± 0.198876). ITS ranked next to trnH-psbA since it was able to generate 100% resolution of species and comparable mean intraspecific distance score with trnH-psbA. rbcL failed to resolve any species correctly, thus it has 0% resolution of species. The proponents of this study recommended to increase sample size and to include species which are difficult to distinguish morphologically to test the discriminatory abilities of the loci.