Molecular systematics of Descurainia (Brassicaceae) in the Canary Islands: biogeographic and taxonomic implications
Authors: Goodson, Barbara E.1; Santos-Guerra, Arnoldo2; Jansen, Robert K.1
Source: Taxon, Volume 55, Number 3, August 2006 , pp. 671-682(12)
Publisher: International Association for Plant Taxonomy
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Abstract:
Descurainia Webb & Berthel. (Brassicaceae) comprises approximately 45 species distributed throughout temperate areas of the world. In contrast to the small-flowered herbaceous taxa which constitute the majority of the genus, the seven species endemic to the Canary Islands are relatively large-flowered woody perennials. A molecular-based phylogeny of Canarian Descurainia was constructed using DNA sequences from nuclear ribosomal internal transcribed spacer (ITS) and seven non-coding chloroplast regions. The results of parsimony and Bayesian analyses suggest that species of Descurainia in the Canary Islands are recently derived via a single colonization event. The closest continental relative is D. tanacetifolia, a perennial herb from the mountains of southwestern Europe. Chloroplast data suggest that both intra-island adaptive radiation and inter-island colonization have played a prominent role in the evolution of Descurainia in the Canary Islands. The most likely ancestral location of the island progenitor was the lowland scrub zone on Tenerife.Keywords: BIOGEOGRAPHY; BRASSICACEAE; DESCURAINIA; CANARY ISLANDS; MACARONESIA; OCEANIC ISLANDS
Document Type: Research article
Affiliations: 1: Section of Integrative Biology and Institute of Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, U.S.A. 2: Jardín de Aclimatación de La Orotava, Instituto Canario de Investigaciones Agrarias, Calle Retama Num. 2, 38400 Puerto de La Cruz, Tenerife, Canary Islands, Spain
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