NICKRENT, DANIEL L. 1*, CHRISTOPHER L. PARKINSON 2, JEFFREY D. PALMER 2, AND R. JOEL DUFF 3. 1 Department of Plant Biology and Center for Systematic Biology, Southern Illinois University, Carbondale, IL, USA 62901-6509, 2 Department of Biology, Indiana University, Bloomington, IN USA 47405, 3 Department of Biology, University of Akron, Akron OH USA 44325-3908. - Parsimony and likelihood analyses of genes from all three subcellular genomes strongly support major land plant phylogenetic relationships.
The evolution of land plants from green algal ancestors has long been
a topic of interest to botanists and has more recently taken on
special interest given results from molecular phylogenetic analyses.
Parsimony and likelihood analyses were conducted on a data set
comprising chloroplast rbcL, and nuclear, chloroplast, and
mitochondrial small-subunit (SSU) rDNA (6095 total characters) from
all major land plant lineages. Significant bootstrap support was
obtained for 1) hornworts as sister to the remaining embryophytes, 2)
a sister-group relationship between mosses and liverworts, and 3)
monophyly of vascular plants, lycophytes, pteridophytes, seed plants,
and angiosperms.. In contrast to the other genes, mitochondrial SSU
rDNA analyzed alone recovered essentially the same topology as the
multigene tree and had the lowest level of homoplasy. The tree
topology obtained here is highly congruent with previous cladistic
analyses of morphological characters, thus strongly suggesting that
the same phylogenetic pattern is being tracked.
Key words: embryophyte, hornwort, liverwort, moss, rbcL, small-subunit ribosomal DNA