title: Reticulate evolution and phylogeography in Asarum sect. Asiasarum (Aristolochiaceae) documented in internal transcribed spacer sequences (ITS) of nuclear ribosomal DNA.
abstract: Phylogenetic analyses were performed for the taxonomically complicated group, Asarum sect. Asiasarum, using internal transcribed spacers (ITS) of nuclear ribosomal DNA. Direct sequences for 99 samples of a total of 14 taxa and geographic races and cloning analyses for 32 of these samples provided new insights that extensive reticulate evolution has occurred in this group. Eight taxa had slight or no polymorphism of the ITS sequences. On the other hand, the other five taxa had polymorphic ITS sequences composed of two ribotypes that were completely the same or almost the same as the sequences recognized in the taxa with only slight or no polymorphism, and were probably of diploid hybrid origin and to have retained their parental ribotypes. In terms of biogeographic implications, at least four interactions including migration, hybridization, and introgression, were presumed between the Japanese Archipelago and the continents, two times via a southern route, from the Korean Peninsula, and two times via a northern route, from Sakhalin or directly from the Eurasian continent.
authors: Biological Institute, Graduate School of Science, Tohoku University, Aoba, Sendai, Japan. yamaji_hiroki@mail.tsumura.co.jp
authors: Hiroki
authors: H
authors: Yamaji
authors: Tatsuya
authors: T
authors: Fukuda
authors: Jun
authors: J
authors: Yokoyama
authors: Jae-Hong
authors: JH
authors: Pak
authors: Chang-zheng
authors: CZ
authors: Zhou
authors: Chun-shu
authors: CS
authors: Yang
authors: Kenji
authors: K
authors: Kondo
authors: Takashi
authors: T
authors: Morota
authors: Shuichi
authors: S
authors: Takeda
authors: Hiroshi
authors: H
authors: Sasaki
authors: Masayuki
authors: M
authors: Maki
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D002467:Cell Nucleus / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D019684:Magnoliopsida / Q000235:genetics*; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000235:genetics; D016415:Sequence Alignment; D014158:Transcription, Genetic / Q000235:genetics*
chemical_list: D004275:DNA, Ribosomal; D009711:Nucleotides