Evaluation of six regions for their potential as DNA barcodes in epiphyllous liverworts from Thailand

PREMISE OF THE STUDY: Studies on the diversity of epiphyllous bryophytes have been limited because of minute and incomplete specimens and a lack of taxonomic expertise. The recent development of the DNA barcoding approach has allowed taxon identification and species discovery of many obscure groups of organisms. METHODS: With DNA extractions from 99 samples of 16 species, we compared the efficiencies of six DNA markers (rbcL, matK, trnL‐F, psbA, ITS1, and ITS2) in their ability to amplify, using a standard set of primers, as well as their discriminatory power, using distance‐based and tree‐based approaches with nucleotide data. RESULTS: The amplification success was relatively high (70–90%) with all of the markers, except for matK, which yielded no success. The barcoding gap, as calculated from the difference between inter‐ and intraspecific genetic distances, was the highest in ITS2, whereas the highest numbers of monophyletic groups were found with ITS2 and rbcL. DISCUSSION: rbcL should be used as a main barcoding marker with the addition of ITS2 for epiphyllous species. The development of DNA barcoding as a tool for quantifying species diversity will provide a rapid and reliable identification tool for epiphyllous bryophytes.