Phylogenetic analysis of Artemisia section Tridentatae (Asteraceae) based on sequences from the internal transcribed spacers (ITS) of nuclear ribosomal DNA

Abstract

Artemisia sect. Tridentatae is composed of 11 species of xerophytic shrubs, which dominate much of western North America. Sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA were used to construct a phylogeny, examine circumscription of the section, resolve interspecific relationships, and test competing hypotheses on the origin of the section. The data support the monophyly of sect. Tridentatae, with the exclusion of A. bigelovii and A. palmeri-two historically, anomolous species. However, the ITS data provide insufficient variation to fully resolve interspecific relationships or to support major lineages within the Tridentata clade. Nuclear and chloroplast DNA phylogenies are discordant, which may be a result of interspecific gene flow and subsequent chloroplast capture, particularly related to the placement of A. filifolia and A. californica, in addition to A. bigelovii. Furthermore, the ITS data are in conflict with cpDNA data, providing equivocal evidence for competing hypotheses on the Old World vs. New World origin for the section and do not provide support for definitive subgeneric placement.

Phylogenetic Taxonomy of Artemisia L. Species from Kazakhstan Based on Matk Analyses

“…Due to the large amount of species in the genus, their classification is still complex and not fully completed. In earlier studies, the genus was subdivided into three subgenera (Poljakov, 1961;Kornkven et al, 1998). Absinthium and Tridentatae subg.…”

Phylogenetic relationships among Artemisia species based on nuclear ITS and chloroplast psbA-trnH DNA markers

“…Our results are also consistent with Bremer & Humphries (1993) who treated the section Serphidium as separate genus from Artemisia s.l., and disagree with other taxonomists such as Kornkven et al (1998Kornkven et al ( , 1999, Torrell et al (1999), who classified Serphidium within Artemisia.…”

“…The taxonomic relationships within the genus Artemisia s.l. is controversial, and over the past 50 years different taxonomic treats have been conducted ranging from a single large genus with over 500 species (Cronquist 1955;Kornkven et al 1998;Kornkven et al 1999;Torrell et al 1999;Martin et al 2001) to the recognition of six to eight genera (Bremer & Humphries 1993;Poljakov 1961;Ling 1994). In the past, the genus Artemisia had been divided into three genera of Artemisia, Absinthium, and Abrotanum, but later all these three genera were considered as a single genus by Linnaeus.…”

“…Moreover, the subgenus Serphidium has been taxonomically treated differently. Many taxonomist separated Serphidium as a distinct genus from Artemisia (e.g., Kornkven et al 1998Kornkven et al , 1999Torrell et al 1999), while Torrell et al (2001) latter disagreed with this separation, and included Serphidium within Artemisia. The current work is aimed to re-investigate the phylogenetic relationships in Artemisia using nuclear ribosomal DNA (ITS) and chloroplast psbA-trnH sequences.…”

The origin, phylogenetics and natural history of darwiniothamnus (Asteraceae: Astereae), an endemic shrub of the Galapagos Islands

“…Baldwin et al, 1995, Kornkven et al, 1998, Noyes and Rieseberg, 1999Torrell, et al, 1999, and Clevinger and Panero, 2000. Indeed, although the ITS region has been especially useful for sorting out the phylogenetics of organisms at the species and genus level, it is rarely used to detect within-species variation (Wem-Hsiung Li, 1997).…”