The majority of the systematic work in my lab is focused on the Malvales. My aim is to reconstruct the group's phylogeny at all levels and to use the results to clarify the pattern of floral evolution in the group and its correlation with shifts in pollination mechanism. The work is funded by the National Science Foundation. In addition to this work in Malvales, graduate students in my lab have worked on a diversity of other plant groups (see below).

The evolution of plant development

Three projects in my laboratory (or in my former lab at Harvard) aim to clarify the genetic basis of morphological evolution.

1. A study of the role of LEAFY in inflorescence evolution in the cabbage family, Brassicaceae. Specifically we are focusing on three genera, Idahoa, Leavenworthia, and Jonopsidium, which produce flowers in the axils of rosette leaves rather than on an elongated, leafless infloresence. More information on the inflorescence evolution project can be found on a companion page. This project is funded by the National Science Foundation.

2. I am interested in studying the phylogeny of the MADS-box gene family in /Malvoideae (Malvales) and exploring their role in floral differentiation. A former post-doc, Alan Yen, cloned a number of floral expressed MADS-box genes (including AP3 and PI orthologs) and characterized their whorl-specific expression in dissected flowers. In the future I hope to evaluate the hypothesis that the production of a petaloid calyx and epicalyx in Goethea (Pavonia) strictiflora is correlated with an expansion of the expression of the B-group genes into those whorls.

3. Véronica Di Stilio is studying the genetic basis of sexual dimorphism in dioecious meadow rues (Thalictrum, Ranunculaceae). She has cloned florally expressed B-group MADS-box genes and has compared their expression in carpellate ("female") and staminate ("male) flowers. She is testing the hypothesis that unisexual flowers are formed via homeotic conversion of stamens into carpels in female flowers and carpels into stamens in male flowers. Since my move to Madison, Veronica's project continues in the laboratory of my colleague Elena Kramer. Some elements of this project will hopefully continue in Madison.

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Theoretical Interests

In addition, to empirical projects I spend a portion of my time working on phylogenetic and evolutionary theory. I am particularly interested in understanding the nature of "species" as products of evolutionary history. To this end I have delved into some of the philosophical literature dealing with the ontology of individuals. I am also interested in clarifying the theory behind the testing of hypotheses of adaptation. My current project in this regard is the development of a Bayesian framework for estimating the strength of selection acting when a character under study went to fixation. Lastly, I have been dabbling in the problem of homology and attempting to bring the philosophy of individuality to bear.