Chin, Siewwai , Wen, Jun , Shaw, Joey , Haberle, Rosemarie , Perez Zabala, Jorge , Potter, Daniel .
Phylogeny and Historical Biogeography of Prunus (Rosaceae, Amygdaloideae).
The genus Prunus, widely distributed in both the Old and New Worlds,comprises 200-400 species of trees and shrubs and includes many of the most economically important fruit crops of temperate regions, as well as species used for a range of other purposes. Best known from the temperate zone of the Northern Hemisphere, the genus is also well represented in tropical regions in Asia and the Americas, though species from the latter areas have received relatively little attention to date. Phylogenetic analyses of plastid DNA provide support for the following: 1) a clade comprised of members of subgenera Prunus (with section Microcerasus cherries embedded), Amygdalus, and Emplectocladus; 2) a clade comprising most members of subgenus Cerasus; 3) a clade comprising clades 1) and 2); and 4) a clade comprised of tropical and temperate members of subgenera Laurocerasus and Padus (with genus Maddenia embedded). In contrast, analyses of nuclear ribosomal ITS sequences provide support for Clades 1) and 2), but not 3) and 4), and some topologies resolve Cerasus as more closely related to temperate members of Laurocerasus and Padus than to Clade 1). In addition, the ITS data suggest that the tropical African, American, and southeast Asian species form several distinct and geographically consistent clades. Taken together with the fact that documented chromosome counts indicate that subgenera Laurocerasus and Padus are polyploid groups, our results suggest that an early hybridization in the genus, involving an ancestral cherry on the paternal side and another early-diverging lineage on the maternal side, gave rise to the common ancestor of extant Laurocerasus and Padus. Reconstructions of ancestral areas in conjunction with clade dating indicate that the genus originated in eastern Asia in the late Paleocene and that the proposed hybridization event that resulted in the divergence of clades 3) and 4) in the plastid phylogeny occurred in the same area in the early Eocene. Subsequent diversification of clade 1) included at least two separate dispersals into North America, most likely via the Bering land bridge. Diversification of clade 4) involved dispersals into southeast Asia and Africa, as well as at least two to the New World, one most likely via the North Atlantic land bridge, the second possibly via the Bering land bridge and extending into Central and South America. Our study includes greater representation of tropical taxa than in previous analyses, but increased sampling from some areas is needed to test these hypotheses.
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1 - University Of California Davis, Plant Sciences, 1 Shields Avenue Mail Stop 2, Davis, CA, 95616, USA
2 - Smithsonian Institution, Botany, MRC-166 National Museum Of Natural History, 10th St. & Constitution Ave., NW, MRC 166, Washington/DC, N/A, 20013-7012, USA
3 - University Of Tennessee At Chattanooga, DEPARTMENT OF BIOLOGICAL AND ENVORONMENTAL SCIENCE, DEPT 2653, 615 MCCALLIE AVENUE, CHATTANOOGA, TN, 37403-2598, USA
4 - Pacific Lutheran University, Biology Dept., 1010 122nd St S, Tacoma, WA, 98447-0003, USA
5 - University of California, Davis, Plant Sciences, Department of Plant Sciences Mail Stop 2, University of California 1 Shields Avenue, Davis, CA, 95616, USA
6 - University Of California Davis, DEPARTMENT OF PLANT SCIENCES MAIL STOP 2, One Shields Avenue, Davis, CA, 95616-8780, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Franklin A/Hyatt
Date: Monday, July 9th, 2012
Time: 2:45 PM