Systematics Section / ASPT
Yuan, Yaowu , Olmstead, Richard .
Phylogenetic Utility of the Phot Gene Duplicates in the Verbena complex (Verbenaceae): Implications for Hybridization and Introgression among Diploid Verbena Species.
The Verbena complex includes Verbena, Glandularia, and Junellia, with each genus containing 40 to 50 species, predominantly distributed in temperate South and North America. Our previous studies based on chloroplast DNA and nuclear waxy gene sequence data suggested that Junellia is paraphyletic and ancestral among the three genera; both Glandularia and Verbena are monophyletic and have been derived from within Junellia. These data also indicated two independent intergeneric chloroplast transfers, both from Verbena to Glandularia. To test these hypotheses, we cloned and sequenced another two nuclear gene loci, Phot1 and Phot2, independently evolving paralogs from an ancient gene duplication, dating to at least before the divergence of monocots from dicots. The Phot1 and Phot2 gene trees corroborate previous results in that both Verbena and Glandularia are monophyletic and support the “chloroplast transfer” hypothesis. These gene trees also provide further information to understand the biogeography of this group. It is mostly likely that both Verbena and Glandularia originated in South America and dispersed to North America independently. Within the major clades, relationships between species are incongruent among the waxy, Phot1, and Phot2 gene trees, due to incomplete lineage sorting. However, these gene trees consistently suggest there are three probable cases of hybridization and introgression among the diploid N. American Verbena species. Since this study represents the first phylogenetic application of the Phot gene duplicates, we have designed a set of universal amplification and sequencing primers for the Lamiales at both loci. A strategy of using “SINE display” in studying hybridization and introgression at population level will be briefly discussed as well.
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1 - University of Washington, Department of Biology, Po Box 35-1800, Seattle, Washington, 98195-1800, USA
2 - University of Washington, Department of Biology and Burke Museum, Box 355325, Seattle, WA, 98195, USA
Presentation Type: Oral Paper:Papers for Sections
Location: International Ballroom South/Hilton
Date: Wednesday, July 11th, 2007
Time: 2:15 PM