Phylogeny of Weigela and Diervilla (Caprifoliaceae) Based on Nuclear rDNA ITS Sequences: Biogeographic and Taxonomic Implications |
| |
Authors: | Young-Dong Kim Sung-Hee Kim |
| |
Institution: | (1) Department of Biology, Hallym University, Chunchon 200–702 Korea, KR |
| |
Abstract: | Weigela and three species of Diervilla were inferred from nucleotide sequence variation in the internal transcribed spacer (ITS) regions of 18-26S nuclear ribosomal
DNA. Phylogenetic trees were obtained using parsimony, distance, and maximum likelihood methods. The ITS phylogenies did not
support the monophyly of Weigela, which comprises three major clades. The first clade includes a single species, W. middendorffiana, which is more closely related with American genus, Diervilla. The second clade consisted of a single species, W. maximowiczii, but its relationship to other Weigela species is equivocal. The third one is a strongly supported core clade which contains the remaining Weigela species. Within the core group, W. hortensis exhibits the most distinct ITS sequence type. The hybrid origin of the species from the putative parents, W. florida and W. subsessilis, is not supported. The ITS sequence evidence favors the taxonomic hypothesis proposed by Nakai who recognized four distinct
evolutionary lines (Diervilla, Macrodiervilla, Weigelastrum and Weigela). However, recognition of the two sections, Calysphyrum and Weigela was not supported in the ITS phylogenies. Substantial morphological differences between Diervilla and Weigela middendorffiana do not support the morphological stasis concept which has been considered as a general evolutionary mode among the Asian
and North American disjunct taxa.
Received 27 July 1998/ Accepted in revised form 7 July 1999 |
| |
Keywords: | : Diervilla Disjunct taxa ITS Paraphyletic group Phylogeny Weigela |
本文献已被 SpringerLink 等数据库收录! |
|