Molecular Evidence for the Hybridity of Ilex x wandoensis and the Phylogenetic Study of Korean Ilex Based on ITS Sequence Data

Abstract

In this study, internal transcribed spacer (ITS) regions within the nuclear ribosomal DNA of Korean Ilex were analyzed in order to investigate any molecular evidence that I. x wandoensis could serve as a putative hybrid between I. cornuta and I. integra. We also sought to clearly identify taxonomic relationships and problems caused by consecutive external morphological characters among taxa in the genus. We sequenced 20 clones from I. x wandoensis and found these individuals displayed intra-genomic polymorphisms within ITS regions. The analysis of the clones clearly demonstrated the presence of discrete sequences from both I. cornuta and I. integra, thereby confirming I. x wandoensis is a species that was formed by crossing I. carnuta and I. integra, Lastly, the subgenus Ilex, which contains the evergreen species, failed to form a monophyletic group in a strict consensus tree that was prepared based upon ITS regions. I. crenata var. microphylla in the subgenus Korea Ilex, which has presented taxonomic problems previously, formed an independent clade within the consensus tree, thereby showing distinction from I. crenata.) Genetic discontinuity of I. macropoda and I. Macropoda for. pseudo-macropoda individuals couldn't be confirmed.