Majure, Lucas C. , Griffith, M. Patrick , Puente, Raul , Judd, Walter S. , Soltis, Pamela S. , Soltis, Douglas E. .
Phylogeny reconstruction of the genus Opuntia (Cactaceae) and its evolutionary significance.
The genus Opuntia (Cactaceae) is found throughout the Americas from Canada to Argentina. Species rich areas include the desert Southwest of the United States, northern Mexico, and arid areas of South America and the Caribbean. The major clades and evolutionary relationships among species of the genus are not well known, as no comprehensive phylogeny of the genus has ever been produced. There are roughly 120-200 species in the genus, however, species limits are understudied and their understanding is further made difficult by widely exhibited morphological variation, frequent interspecific hybridization, and rampant polyploidy. We used molecular data from four plastid intergenic spacer regions and the nuclear ribosomal internally transcribed spacer (nrITS) to reconstruct the phylogeny and determine the major clades in Opuntia using maximum parsimony, maximum likelihood, and Bayesian methods. More than 12 major clades were recovered, some of which consist entirely of polyploid taxa. The genus Nopalea, although forming a well-supported clade, was nested within the genus Opuntia, suggesting that Nopalea should be treated within Opuntia to avoid making a paraphyletic assemblage of taxa. Clades do not necessarily correspond to geographic regions, since for example, the Caribbean taxa were found scattered throughout the phylogenetic tree. Although more extensive taxon sampling is necessary to resolve fully the phylogeny of Opuntia, our phylogeny provides the framework for future studies of the systematics of the group and for the study of the evolutionary consequences of polyploidy.
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1 - University of Florida, Department of Biology, Florida Museum of Natural History, P.O. Box 117800, Gainesville, FL, 32611-7800, USA
2 - Montgomery Botanical Center, 11901 Old Cutler Road, Miami, Florida, 33156, USA
3 - Desert Botanical Garden, 1201 N Galvin Parkway, Phoenix, AZ, 85008, USA
4 - University of Florida, Department of Biology, 220 Bartram Hall, P.O. Box 118526, Gainesville, FL, 32611, USA
5 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611-7800, USA
6 - University of Florida, Department of Biology, 220 Bartram Hall, P.O. Box 118526, Gainesville, FL, 32611, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 554/Convention Center
Date: Wednesday, August 4th, 2010
Time: 3:45 PM