HILU, KHIDIR W*, THOMAS BORSCH2, JENS ROHWER3, CHRISTOPH NEINHUIS2, TRACEY SLOTTA1, BIRGIT GEMEINHOLZER4, MICHAEL WINK4, AND LAWRENCE A. ALICE5. 1Department of Biology, Virginia Tech, Blacksburg, VA, 24061; 2Botanisches Institut und Botanischer Garten, Universität Bonn, Germany; 3Institut für Spezielle Botanik, Johannes Gutenberg Universität, 55099 Mainz, Germany; 4Institut für Pharmazeutische Biologie, INF 364, 69120 Heidelberg, Germany; 5Department of Biology and Biotechnology Center, Western Kentucky University, Bowling Green, KY, 42101. - Insight into the evolution of angiosperms: evidence from matK sequences.
We analyzed DNA sequences of the plastid gene matK to infer
phylogenetic relationships among angiosperms. Our sample includes
seven monocot families (Anthericaceae, Asparagaceae, Convallariaceae,
Joinvilleaceae, Poaceae, Restionaceae, and Trilliaceae) and 19 dicot
families (Amborellaceae, Anthospermataceae, Brassicaceae,
Calycanthaceae, Ericaceae, Fabaceae, Hamamelidaceae, Hernandiaceae,
Illiciaceae, Lauraceae, Loganiaceae, Magnoliaceae, Monimiaceae,
Nymphaeaceae, Paeoniaceae, Rosaceae, Rubiaceae, Saxifragaceae, and
Scrophulariaceae). The tree is rooted with three families of conifers
(Pinaceae, Cupressaceae, and Taxaceae) plus Gnetum (Gnetaceae).
Including all species (Amborella and Illicium are
missing the 5' one-third of the gene), the angiosperms are strongly
supported as monophyletic. The base is a polytomy of six lineages:
Amborella, Illicium, monocots, Nymphaeales, magnoliids,
and tricolpates. Magnoliaceae are sister to all other members of the
Magnoliid complex sampled. Saxifragales species form a clade with the
rosids that is sister to the asterid clade. When Amborella and
Illicium are excluded from the analysis, a single most
parsimonious tree is recovered with a CI of 0.47 and an RI of 0.70
excluding uninformative characters. This tree shows Nymphaeales
(bootstrap of 100%) as sister to the other angiosperms; the latter are
divided into two large clades with the magnoliids (99%) sister to the
tricolpates (97%). Additionally, the Nymphaeales are supported by a
12-bp insertion, the monocots by a different 12-bp insertion, and the
tricolpates by a 9-bp deletion.
Key words: angiosperms, cladistics, evolution, matK, phylogeny