My research focuses on understanding the evolutionary, developmental, and ecological processes responsible for land plant diversity. The analysis of character evolution using tools from molecular phylogenetics and molecular genetics forms the core of this research. In particular, fascination with plant form, plant morphogenesis, and plant development fuel these interests. Currently, I am examining the evolutionary and developmental mechanisms responsible for water storage tissue in stems and roots (i.e., plant succulence). Stem succulence provides a classic example of convergent evolution, as over thirty lineages have evolved stem succulence. I predicted that shared (homologous) developmental modules are switched on and off during evolution to account for multiple origins of succulent growth habits. My lab is undertaking phylogenetic, bioinformatic, anatomical, and molecular genetic analyses in Brassica, Arabidopsis, Vitaceae, and Passifloraceae to understand what aspects of succulence evolution and development are shared and which aspects differ among distantly related lineages. Such an understanding will contribute to a richer picture of mechanisms of anatomical patterning, and, in the process, gene regulatory mechanisms may be discovered that can generate storage-rooted and succulent-stemmed crops. Additional projects include the analysis of biological shape, biodiversity informatics, and computational approaches to characterize plants in an automated fashion. At its most general, my lab focuses on the patterns and processes of biological pattern formation and employs computational/bioinformatic, mathematical, field and lab experimental approaches.
Wang, D., Zhang, C., Hearn, D. J., Kang, I.-H., Punwani, J. A., Skaggs, M. I., Drews, G. N., Schumaker, K. S., and R. Yadegari. (in review). Identification of transcription-factor genes expressed in the Arabidopsis female gametophyte. Submitted to Plant Physiology.
Hearn, D. J. 2009. Developmental patterns in anatomy are shared among separate evolutionary origins of stem succulent and storage root-bearing growth habits in Adenia (Passifloraceae). American Journal of Botany. In press.
Estes, A. M., Hearn, D. J., Bronstein, J., and E. Pierson. 2009. The olive fly endosymbiont, "Candidatus Erwinia dacicola", switches from an intracellular to an extracellular existence during host insect development. Applied Environmental Microbiology. In press.
Hearn, D. J. 2009. Shape analysis for the automated identification of plants from images of leaves. Taxon 58: 934-954.