70 Years After Schultes: Economic Botany from the Andes to the Amazon
Islam, Melissa , Ranker, Tom .
The Evolutionary History of the Cultivated Cocas (Erythroxylum).
The tropical, flowering shrubs in the genus Erythroxylum P. Brown (230 species) are commonly known as coca and occur throughout the tropics. Two species each with two varieties are exploited for their production of the secondary metabolite, cocaine. Most studies of coca are devoted to understanding the economic and medical impact of the legal and illegal uses of cocaine. Until now, the evolutionary relationships among the cultivated species and their closest wild relatives remained untested in a modern phylogenetic framework. Based on their morphological similarity, the cultivated species were hypothesized to be more closely related to each other than to any other Erythroxylum species. Both species belong to section Archerythroxylum, which should include their closest relatives. This section includes approximately 60 species from the Neotropics. Two nuclear loci (nrITS and idhb) and one chloroplast locus (rpL32F), along with morphological characters, was sampled from approximately 70 species to infer the evolutionary relationships among the cultivated species and to determine their closest wild relatives. The idhb locus was sampled from only 35 species. Based on the phylogenetic analyses, the two cultivated species, E. coca Lam. and E. novogranatense (Morris) Hieron, and their varieties form separate well-supported clades and are supported as distinct species. Although the two cultivated species are closely related, their monophyly is not supported. Their closest wild relatives are Archerythroxylum species with deciduous leaves.
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1 - Denver Botanic Gardens, Research & Conservation, Denver, CO, 80206, USA
2 - University of Hawaii at Manoa, Department of Botany, 3190 Maile Way, Room 101, Honolulu, HI, 96822, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Maryland Room/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 4:00 PM