Systematics Section / ASPT
Yuan, Yaowu , Olmstead, Richard .
A comparison of chloroplast and nuclear gene phylogeny of the Verbena complex (Verbenaceae): evidence for chloroplast transfers.
THE Verbena complex includes Verbena, Glandularia, and Junellia, with each genus containing 40 to 50 species. While Junellia (basic chromosome number x=10) is restricted to South America, both Glandularia (x=5) and Verbena (x=7) have a disjunct distribution, with diploid and polyploidy species restricted to either the North or South American continents. Five non-coding chloroplast DNA regions, trnT-L, trnD-T, trnL-F, trnS-G, and trnfM-trnS, totaling >5 kb, were sequenced for 53 Verbena complex species and 6 outgroup species. The low sequence divergence implies a recent diversification of this group. The cpDNA phylogeny suggests that none of these three genera is monophyletic. However, the phylogeny based on 3kb of the nuclear gene GBSSI suggests that both Verbena and Glandularia (excluding Glandularia crithmifolia) are monophyletic. Shifting one Glandularia clade from the sister branch of the South American Verbena clade to a position on another Glandularia clade on the cpDNA tree will result in a cpDNA phylogeny consistent with the nuclear GBSSI phylogeny. This indicates an ancient chloroplast transfer from the South American Verbena to the common ancestor of this Glandularia clade. Glandularia bipinnatifida may represent a more recent chloroplast transfer from a North American Verbena species to at least one population of Glandularia bipinnatifida.
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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, Box 355325, Seattle, Washington, 98195-5325, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 31st, 2006
Time: 10:30 AM