Systematics Section / ASPT
Dertien, Joseph R. , Duvall, Melvin R. , Beck, Hans T. .
Using molecular systematic techniques for taxonomic assessment and potential conservation of an endangered tree (Guaiacum spp.).
Lignum-vitae or guayacan (Guaiacum officinale and G. sanctum, Zygophyllaceae) is a slow growing and long lived tree of historical significance and economic value. The current taxonomy of Guaiacum is widely recognized as uncertain, with an understanding of approximately six species but including over 20 known synonyms. This ambiguity has direct bearing on international trade regulation (CITES) as well as proper assessment of endangerment or extinction risk. The goal of this research is to use molecular systematic techniques to investigate genetic variation in Guaiacum species and in allied genera (Bulnesia, Larrea, Porlieria and Viscainoa). This will result in the determination of taxonomic boundaries in Guaiacum and related taxa as well as the assessment of molecular variation with suitable resolution to distinguish potential subpopulations of Guaiacum officinale for future conservation efforts. Levels of variation in DNA sequences are being determined for two maternally inherited regions (chloroplast trnL-F and the variable 3' region of ndhF) as well as a biparentally inherited region (ITS) for Guaiacum and closely related species. Sequences of trnL-F contain sufficient insertion/deletion mutations and single nucleotide polymorphisms to effectively distinguish at least three species, while a preliminary screening of ndhF has demonstrated inadequate variation for species level distinction. Comparative phylogenetic analyses will be used to elucidate potential interpopulational and interspecific gene flow. This genetic assessment has direct conservation applications: wild populations are in decline, and commercially-grown sources may play a significant role in restoration plans and management programs.
1 - Northern Illinois University, Department of Biological Sciences, Montgomery Hall, DeKalb, Illinois, 60115, USA
Presentation Type: Paper
Location: Cottonwood A (Snowbird Center)
Date: Wednesday, August 4th, 2004
Time: 3:00 PM