I am currently a Postodoctoral Fellow in the Mathematical Biosciences Institute at the Ohio State University. My general research interests lie in the interdisciplinary field of Systems Biology; in using tools from the physical sciences--physics, engineering, mathematics, and computer science--to probe living systems and attempt to understand biological function. Below I describe some of my current research projects. (Please keep in mind that this page is a constant work in progress.)

That populations and individuals are not the same thing is something that we scientists sometimes conveniently forget. The distinction is important, as there are some details of individual behavior that cannot be determined by studying populations alone. Still, if we're just a little clever, there might be a few more details that we can squeeze out of population-level data; for example, in a recent paper we presented a deconvolution method for getting "individual-like" information from a cellular population. Work in this area is ongoing.

It is thought that bistability (i.e., the ability to adopt one of two different stable states) in gene regulatory networks can play an important role in cell fate decisions, such as that made by pluripotent epidermal cells in the model plant Arabidopsis thaliana. The picture below (taken with an environmental scanning electron microscope) shows the results of this particular cell fate 'choice': some cells differentiate into large, branched trichomes, while others become terminal leaf pavement cells. So why does this kind of thing happen? Well, it turns out that there are quite a lot of ways to make toggle switches out of genes and proteins. I'm currently working on understanding some of the rules of the switch-building game.

There are a number of other projects, spanning the biological network size/complexity spectrum, that I'm presently engaged in: from building dynamical models of small developmental network motifs, to getting at better estimates of cell cycle network parameters, to establishing genome-wide hierarchical coexpression networks. I believe that a detailed understanding of the fundamental 'mechanisms of life' will ultimately require analyses running the gamut of biological scales, and I can only hope that at least some part of my research will play a small role in elucidating those mechanisms.

Erich Grotewold (Ohio State)
Josh Ash (Ohio State)
Greg Smith (William & Mary)
Kengo Morohashi (Ohio State)
Jasmine Zhou (USC)
Wenyuan Li (USC)
Xiling Shen (Cornell)
Shenghua Li (Rochester)
Marisa Eisenberg (Ohio State)

· Fiebig, A., Castro Rojas, C.M., Siegal-Gaskins, D., and Crosson, S. 2010. Interaction specificity and toxicity in a paralogous set of ParE/RelE-family toxin-antitoxin systems. In revision.

· Siegal-Gaskins, D., Grotewold, E., and Smith, G.D. 2009. The capacity for multistability in small gene regulatory networks. BMC Syst. Biol. 3:96. [HTML/PDF]

· Siegal-Gaskins, D., Ash, J.N., and Crosson, S. 2009. Model-based Deconvolution of Cell Cycle Time-series Data Reveals Gene Expression Details at High Resolution. PLoS Comp. Biol. 5(8): e1000460.[HTML/PDF]

· Guet C., Bruneaux L., Min T.L., Siegal-Gaskins D., Figueroa I., Emonet T. and Cluzel P. 2008. Minimally invasive determination of mRNA concentration in single living bacteria, Nucleic Acids Res. 1-8. [HTML/PDF]

· Siegal-Gaskins, D., and Crosson, S. 2008. Tightly-regulated and heritable division control in single bacterial cells. Biophys. J. 95:2063-2072. [HTML/PDF]

· Purcell, E.B., Siegal-Gaskins, D., Rawling D.C., Fiebig, A., and Crosson, S.  2007.  A photosensory two-component system regulates bacterial cell attachment.  Proc. Natl. Acad Sci. USA 104:18241-18246. [HTML/PDF]