Phylogenetic relationship between Dendropanax morbifera leveille and D.trifidus makino (Araliaceae) based on nuclear ribosomal DNA internal transcribed spacer (ITS) sequences

摘要

Dendropanax morbifera Leveille known as a Korean endemic plant and D. trifidus Makino distributed in Japan have been identified as different species. Some biologists have proposed that both plants should be considered as the same species based on their morphological resemblance, uncertainty of discrimination characters and previous molecular evidence revealed by RAPD analysis. Sequences of internal transcribed spacers (ITS) regions of the nuclear ribosomal DNA (nrDNA) repeats were obtained from each species to reconstruct phylogenetic relationships. The comparison of ITS sequences in the two species through multiple alignments showed similarity between them. Especially, the sequence of Tsushima of D.trifidus Makino revealed 2 insertion/deletion fragments, one of those was 3 base pairs (bp) longer in ITSI region and the other was 21 bp longer in ITSII region. These fragments appeared only in Tsushima specimen, and moreover, were excluded in family Araliaceae. also, phylogenetic trees did not even make a difference inter-species but formed mixed branches. With these results, we are convinced that the two taxa are the same species, because they were indistinguishable.