Garcia, Nicolas , Meerow, Alan , Soltis, Pamela , Soltis, Douglas .
Phylogenetic Structure In
Amaryllidaceae Tribe Hippeastreae (Asparagales) Gains Resolution With
An Expanded ITS Tree .
Amaryllidaceae tribe Hippeastreae constitutes a horticulturally valuable group of petaloid monocots;however, its taxonomy at the generic level has been controversial,with several segregates proposed during the last 40 years. Previous phylogenetic analyses of the nrDNA ITS/5.8S region showed that certain genera are not monophyletic, but lacked good representation of Chilean-Argentinean groups. The hypothesis of possible early lineage reticulation in the tribe was suggested. We have expanded the taxon sampling for this data set by including members of the Chilean endemic genera and additional species of Habranthus,Rhodophiala, Rhodolirium, Sprekelia, and Zephyranthes. A total of approximately 110 species correponds to more than 60% of the tribe's species-level diversity. The tribe comprises two major clades: a) Traubia, Placea,Phycella, Rhodolirium, and Famatina maulensis,characterized by n = 8, lack of polyploidy, and a capitate stigma, and b) Rhodophiala, Habranthus, Hippeastrum,Sprekelia, Zephyranthes, and the remainder of Famatina,characterized by several basic chromosome numbers ranging between n= 6 - 11, and frequent polyploidy and aneuploidy. No clear morphological features diagnose the latter clade. The first group appears to be composed of three main subclades, each with high bootstrap support (>99%). The other major clade appears to be composed of four lineages with unresolved relationships, as shown in previous studies based on ITS and plastid regions, even though the latter have been poorly sampled in terms of taxa. Certain species within Hippeastrum, Rhodophiala, Placea,and Phycella have identical or almost identical sequences to others, implying interspecific nrDNA concerted evolution and/or perhaps rapid radiations within these groups. We are currently working with low-copy nuclear genes and several plastid regions to test further this ITS-based phylogenetic hypothesis. A robust phylogenetic framework will serve as a basis for reclassification of the group and for study of its chromosomal evolution, and will facilitate several tests of the ancient inter-clade reticulation hypothesis in Hippeastreae.
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1 - University Of Florida, Florida Museum Of Natural History, Dickinson Hall, Gainesville, FL, 32611, USA
2 - USDA-ARS-SHRS, UNITED STATES DEPARTMENT OF AGRICULTURE, 13601 Old Cutler Road, Miami, FL, 33158, USA
3 - University of Florida, Florida Museum of Natural History, Gainesville, FL, 32611, USA
4 - University of Florida, Department of Biology, Gainesville, FL, 32611, USA
Presentation Type: Poster:Posters for Sections
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM