Elizabeth A. Zimmer

Smithsonian Institution/Duke University/U Maryland

Current Research Activities:
The majority of current research projects in my laboratory involve studies of the pattern and process of molecular evolution in vascular plants. For two decades, I have been involved in adapting molecular genetics techniques to molecular evolution and systematics studies (Zimmer et al., 1993). I have promoted the use of nuclear ribosomal genes as good models for both phylogenetic and evolutionary process studies, both because they can be used to examine both "deep" and recent branching events among plant species (Hamby and Zimmer, 1992; Wen and Zimmer, 1996; Hershkovitz and Zimmer, 1997) and because they are a multigene family, undergoing concerted evolution (Zimmer et al., 1980; Zimmer, Jupe and Walbot, 1988) and differential gene expression (Jupe and Zimmer, 1993). Our initial work using ribosomal coding sequences identified "paleoherbaceous" groups such as the water lilies (Nymphaeales) and Piperales as early branching lineages in flowering plant evolution (Zimmer et al., 1989) and also contributed to a better understanding of green algal phylogeny (Zechman et al., 1990). More recently, in collaboration with Douglas and Pamela Soltis' and Yin-Long Qiu's laboratories, we have been involved in collaborations combining ribosomal coding region and chloroplast gene data to examine the question of angiosperm origins in more detail (Soltis et al, 1997; Qiu et al., 1999). My laboratory's focus, within basal angiosperm groups, has been on the Winterales and Piperales (Karol et al., 2000; Jaramillo and Zimmer, preliminary results), whereas deeper in vascular plant phylogeny, we are interested in basal groups of ferns, in collaboration with Diana Stein and Judith Skog. With Dr. Skog, we are particularly interested in linking molecular and morphological studies of modern ferns with paleontological data.

Relationship to the Proposed Project:
I am excited about this RCN proposal because it would allow me to interact with plant molecular geneticists on a regular basis, as I did during my postdoctoral training. This kind of interaction has been less accessible to me in my position at the Smithsonian, so the opportunity to host visiting grad students specializing in molecular genetics and to get up to date on current techniques being developed for comparative genomics would greatly benefit both my own research group and those working on animal systems here at the Smithsonian. I am particularly interested in exploring the possibility of comparative gene expression studies in reproductive and vegetative tissues of ferns and some of the basal angiosperm and basal eudicot groups as well as in more recent flowering plant radiations such as the gesneriads (African violet family) and the Caryophyllales (including the cactus and carnation families; Hershkovitz and Zimmer, 1997), where I have been collaborating on molecular systematics with Smithsonian curators Laurence Skog and Warren Wagner, respectively. Gene family studies are also of interest to me, both because of my historical interest in the patterns of and mechanisms producing concerted evolution and because I believe a complete understanding of the molecular genetics and evolution of low copy number nuclear genes is essential to applying them to systematics studies. Current interest in using the introns of this class of plant genes to provide additional resolution for phylogenies of recently-derived plant lineages makes it essential to have a better understanding of multigene family behavior at both the genomic and expression levels.