Beck, James , Oberle, Brad J. , Schaal, Barbara .
Distributional data indicate recent, human-mediated range expansion of Arabidopsis thaliana, an accidentally introduced species in North America.
Non-native species are thought to frequently be in drift/gene flow non-equilibrium, due to both demographic stochasticity and recent range expansion into new geographic regions. As non-native species form an increasingly large portion of local biotas, and as some become problematic invasives, understanding non-equilibrium population genetic structure and its effect on adaptation will become critical. According to most authors, the plant model species Arabidopsis thaliana (L.) Heynh. (Brassicaceae) has been recently introduced into North America, and has subsequently spread across the continent. Given the extensive experimental advantages associated with this species, it could serve as a useful model for non-equilibrium population genetic structure and adaptation. However, recent work has suggested that A. thaliana was potentially widespread prior to European settlement, and that its current distribution is therefore not the result of range expansion. An extensive literature review is conducted in order to evaluate range expansion in this species. The timing of the first published A. thaliana records in the 48 continental states is consistent with an 18th century introduction to the East Coast, a 19th century introduction to the West Coast, and a largely 19th century range expansion across the continent. The extent of A. thalianaís range is positively correlated with years since statehood, which is used as a measure of post-Columbian human activity, even after the possibly confounding effect of precipitation is removed. This relationship strongly suggests that the range expansion was recent and human-mediated.
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1 - Washington University, Department of Biology, Campus Box 1137, One Brookings Drive, St. Louis, Missouri, 63130-4899, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Boulevard B/Hilton
Date: Monday, July 9th, 2007
Time: 8:30 AM