Thomas J. Givnish


Henry Allan Gleason Professor of Botany and Environmental Studies

Ph.D. (1976) Princeton University • 315 Birge Hall • 608-262-5718 •

Plant ecology and evolution; adaptive radiation and molecular systematics;
phylogeography; physiological ecology; landscape dynamics

Over the past five years, my colleagues and I have conducted extensive research to document the evolution of the economically most important group of plants on earth – the monocots – supported by a grant of $2.9M by the National Science Foundation under its Assembling the Tree of Life (AToL) Program.

Monocots (including such groups as grasses, sedges, palms, gingers, bananas, orchids, onions, yams, pondweeds, and philodendrons) comprise more than 65,000 species of flowering plants, occur in almost all habitats on Earth, and provide the basis for the great majority of the human diet. Monocots also account for much of the commerce in cut flowers and horticultural bulbs such as crocuses, irises, hyacinths, tulips, and lilies. Previous attempts to analyze relationships among different monocot groups have made substantial progress but have fallen short, perhaps because many major groups diverged more than 90 million years ago, leaving only subtle and difficult-to-detect traces of deep relationships in their form and genetic material.

My colleagues and I used a revolutionary approach to develop a definitive family tree for the monocots. For the first time, we sequenced and analyzed hundreds of whole chloroplast genomes (the circles of DNA inside the green organelles that conduct photosynthesis). Almost all previous studies using DNA to infer plant relationships have relied on sequences of only one or a few genes or spacers between genes. Our approach has provided sequences for more than 80 chloroplast genes and, in some cases, the spacers between them, providing an avalanche of new data with which to assess evolutionary relationships. Our team has also sequenced dozens of transcriptomes – that is, the entire complement of RNA expressed in tissues, primarily from nuclear DNA – from the leaf tissue of representatives of all monocot orders. The unparalleled amount of genetic information from both the plastid and nuclear genomes has allowed us to conduct some of the most powerful analyses to date of relationships among any group of organisms

The resulting insights into the family tree of the monocots will provide the foundation for many new studies in physiology, ecology, biogeography, and genomics. One such analysis has already been published for the bromeliad family; another, on the orchids, is now under review.

Monocot AToL PIs:

Cecile Ané
Jerry Davis
Claude dePamphilis
Tom Givnish
Alejandra Gandolfo
Sean Graham
Jim Leebens-Mack
J. Chris Pires
Dennis Stevenson
Wendy Zomlefer


© 2011 University of Wisconsin Department of Botany

Last updated: 27 November 2011