Systematics Section / ASPT
Oh, Sang-Hun , Manos, Paul S. .
Cups, nuts, and catkins: a phylogeny of Fagaceae based on CRABS CLAW sequences.
FOR the most species-rich family of the Fagales clade, Fagaceae appear to have evolved within a relatively narrow range of morphological possibility. In this striking example of the combined effects of abiotic and biotic selection pressures, character states related to pollination syndrome, and fruit and cupule types have defined taxonomic concepts above the species level. To date, tests of homology have been incomplete due to phylogenetic uncertainty among chestnut and oak lineages. We determined DNA sequences of CRABS CLAW (CRC), a single-copy gene of the YABBY gene family that regulates carpel and nectary development in Arabidopsis, in 35 taxa representing the major lineages of Fagaceae to reconstruct phylogeny and to test concepts of homology. Phylogenetic analyses using Rhoiptelea and Betula as outgroups produced a well-resolved tree with strong support for backbone relationships. The CRC phylogeny is consistent with previous molecular data in resolving Fagus and Trigonobalanus as the first two branches within Fagaceae, respectively. Our CRC data also provided strong support for a clade of species representing Asian Lithocarpus and western North American Chrysolepis. In contrast, the single species of North American Lithocarpus was placed within a strongly supported clade of the remaining chestnut and oak lineages. Within this clade, CRC data also supported a Castanopsis + Castanea clade, and the following set of relationships among Quercus sensu stricto: (Protobalanus – (Quercus + Lobatae)). The CRC phylogeny suggests that the flower-cupules of Asian Lithocarpus may be homologous with the cryptic arrangement of cupule valves to fruits observed in Chrysolepis, and supports a single origin of hypogeal germination in Fagaceae.
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1 - Duke University, Department of Biology, 139 Biological Sciences Building, PO Box 90338, Durham, North Carolina, 27708, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 134/Performing Arts Center
Date: Tuesday, August 1st, 2006
Time: 10:15 AM