Robert A. Price

Mark W. Chase, Douglas E. Soltis, Richard G. Olmstead, David Morgan, Donald H. Les, Brent D. Mishler, Melvin R. Duvall, Robert A. Price, Harold G. Hills, Yin-Long Qiu, Kathleen A. Kron, Jeffrey H. Rettig, Elena Conti, Jeffrey D. Palmer, James R. Manhart, Kenneth J. Sytsma, Helen J. Michaels, W. John Kress, Kenneth G. Karol, W. Dennis Clark, Mikael Hedren, Brandon S. Gaut, Robert K. Jansen, Ki-Joong Kim, Charles F. Wimpee, James F. Smith, Glenn R. Furnier, Steven H. Strauss, Qui-Yun Xiang, Gregory M. Plunkett, Pamela S. Soltis, Susan M. Swensen, Stephen E. Williams, Paul A. Gadek, Christopher J. Quinn, Luis E. Eguiarte, Edward Golenberg, Gerald H. Learn, Jr., Sean W. Graham, Spencer C. H. Barrett, Selvadurai Dayanandan, Victor A. Albert, Phylogenetics of Seed Plants: An Analysis of Nucleotide Sequences from the Plastid Gene rbcL, Annals of the Missouri Botanical Garden, Vol. 80, No. 3 (1993), pp. 528-548+550-580

Extensive variation in synonymous and nonsynonymous rates of substitution was observed among 50 sequences of the gene coding for the large subunit of ribulose-1,5-bisphosphate carboxylase (rbcL) representing bryophyte, conifer, dicot, and monocot taxa. Relative rate tests revealed rate differences of up to 138% for nonsynonymous substitutions and up to 85% for synonymous ones. Within angiosperms, the annual forms evolved more rapidly, on average, than perennial forms. This rate heterogeneity was more extensive at nonsynonymous sites than synonymous ones, and it resulted primarily from a recent acceleration of substitution rate in many groups of angiosperms.

Nucleotide sequences for the chloroplast gene rbcL have been obtained for three species of Salvadoraceae and for the unispecific Pentadiplandraceae, thus completing a survey of all known mustard-oil families. Phylogenetic analyses of the sequences based on maximum parsimony reveal two separate lineages of plants that produce mustard oil glucosides. A major mustard-oil clade comprises the core capparalean families of Brassicaceae, Capparaceae, Gyrostemonaceae, Resedaceae, and Tovariaceae and includes Akania- ceae, Bataceae, Bretschneideraceae, Caricaceae, Koeberliniaceae, Limnanthaceae, Moringaceae, Pentadipland- raceae, Salvadoraceae, and Tropaeolaceae. A second unrelated lineage consists of the genus Drypetes, traditionally placed in Euphorbiaceae. The major mustard-oil clade recovered from the rbcL analysis is congruent in many topological aspects with that found in a recent cladistic study of morphological characters, and in turn the molecular and morphological results confirm Dahlgren's radically expanded Capparales. An approach combining molecular and morphological evidence yields robust support for several lineages within this major mustard-oil clade.

James Rodman, Robert A. Price, Kenneth Karol, Elena Conti, Kenneth J. Systma, Jeffrey D. Palmer, Nucleotide Sequences of the rbcL Gene Indicate Monophyly of Mustard Oil Plants, Annals of the Missouri Botanical Garden, Vol. 80, No. 3 (1993), pp. 686-699