Origin and evolution of the South American endemic Artemisia species (Asteraceae): evidence from molecular phylogeny, ribosomal DNA and genome size data

• Published in: Australian Journal of Botany
• Main Authors: Pellicer, Jaume, Garnatje, Teresa, Molero Briones, Julián, Pustahija, Fatima, Siljak-Yakovlev, S., Vallès, Joan
• Format: Article in Journal/Newspaper
• Language: English
• Published: CSIRO Publishing 2010
• Subjects: Bering Strait
• Online Access: http://hdl.handle.net/10261/81040; https://doi.org/10.1071/BT10047

12 p., gráf. fot. Genus Artemisia is thought to have reached the Americas across the Bering Strait from Asia during the late Tertiary, but the systematic position of the South American endemic species and the migration routes towards the south have not yet been studied. We used nuclear DNA sequences to unravel the interspecific relationships among the South American Artemisia and their connections with the remaining species of the genus, as well as using fluorescent in situ hybridisation and genome size assessments to characterise this polyploid complex. Most of the species are clustered in a monophyletic clade, nested within the American endemic clade, with the exception of A. magellanica Sch. Bip., which appears segregated from the other American species and constitutes a clade together with A. biennis Willd. Fluorescent in situ hybridisation and genome size data revealed that monoploid genome size remains quite constant across ploidy levels and a proportional increase of ribosomal loci was detected, a dynamic not usually found in this genus. The results are discussed in the light of evolutionary processes which occur in plants, and plausible origins for the South American endemic species are hypothesised. This work was subsidised by DGICYT (Spanish Government; projects CGL2007–64839-C02–01/BOS and CGL2007–64839-C02–02/BOS) and by the Generalitat de Catalunya (projects: 2005-SGR-00344 and 2009-SGR-00439). J. P. received a predoctoral grant from the Spanish Government (FPI program). Peer reviewed