Systematics Section / ASPT
Dertien, Joseph R. , Duvall, Melvin R. .
Systematics and molecular conservation genetics of endangered trees of the dry neotropics (Guaiacum; Zygophyllaceae).
Clarification of the evolutionary relationships within Guaiacum are important to the continued survival of these economically important and globally endangered trees and shrubs of the dry neotropics. Deciphering these relationships will serve to delineate Guaiacum species and possibly identify genetically significant populations. This outcome will have direct impact and application to issues of tropical conservation and commercial trade of these historically over-harvested IUCN and CITES listed plants.
In a broader context, these relationships will also address general questions regarding lineage divergence, phylogeographic patterns, and provide insight towards the nature of gene flow and speciation in fragmented plant populations. The relationships within Guaiacum and relationships among allied genera in Larreoideae (Zygophyllaceae) are being explored using sequence data from three highly variable DNA markers (trnL-F, trnS-G, ITS). Sampling strategies and data analyses incorporate methodologies from the traditionally separate fields of systematics and population genetics to resolve relationships at several taxonomic levels. This fusion of methodologies has indicated genetic patterns in G. sanctum that may have been missed using traditional phylogenetic methods, including a genetic divergence between Puerto Rican and Mexican populations of G. sanctum. These analyses have also revealed that the last remaining population of G. sanctum (Lignumvitae) in the Florida Keys shares haplotypes with both Mexican and Puerto Rican populations. These analyses also suggest a novel molecular relationship between the Guatemalan endemic G. guatemalense and Caribbean G. officinale. These results are of particular significance because they pertain to interspecific and intraspecific genetic exchange, which are key factors involved in plant speciation and are highly relevant to conservation and resource management efforts.
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1 - Northern Illinois University, Department of Biological Sciences, Montgomery Hall, DeKalb, Illinois, 60115-2861, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Boulevard C/Hilton
Date: Wednesday, July 11th, 2007
Time: 11:15 AM