LEE, JUNGHO1,2*, OLENA DOMBROVSKA1,2, MARGARET HOEY1,3, BARBARA A. WHITLOCK1, and YIN-LONG QIU1,2. 1Biology Department, University of Massachusetts, Amherst, MA 01003; 2Institute of Systematic Botany, University of Zurich, 8008 Zurich, Switzerland; 3Fitchburg State University, Fitchburg, MA 01420. - A phylogenetic analysis of land plants using four genes from three genomes.
Over the last several years, the phylogeny of land plants and its
various associated issues have been investigated using analyses of
single to multiple genes with different extent of taxon sampling,
morphological data, and organellar genomic structural characters. At
present, the following issues remain contentious: the first lineage of
land plants, the sister lineage of vascular plants, relationships
among Equisetum, Psilotaceae, eusporangiate and leptosporangiate
ferns, monophyly of extant gymnosperms, and the exact position of
Gnetales. Here we analyze a data set of four mitochondrial (atp1 and
LSU rDNA), plastid (rbcL), and nuclear (18S rDNA) genes from 150
species of land plants. We explore the effectiveness of this broad,
moderately dense taxon and character sampling strategy in
reconstructing the land plant phylogeny. The random outgroup rooting
strategy was employed to evaluate validity of charophytes as an
outgrup to land plants. We also examine substitution rates of these
genes across land plants and use the sequence data to estimate
divergence times of land plants as well as its various component
clades.
Key words: land plant phylogeny, multigene analysis