Our laboratory has two areas of research focus. Of primary interest is the digestive ecology and enzymology of echinoderms and molluscs, with a recent emphasis upon the gastropods Arion ater (common garden slug) and Ariolimax columbianus (banana slug). We wish to know the regulatory factors which govern the release of the various enzymes (proteases, cellulases, chitinases, etc.) into the lumen of the digestive tract and the extent to which those enzymes are contributed by the bacterial symbionts which inhabit the digestive tract, as opposed to their release by the animal itself.

Secondarily, we are interested in the biology and evolution of certain neurological disorders (primarily ADHD) and the relationship of those disorders to an organism’s fluctuating asymmetry (a small deviation from perfect symmetry in traits which are normally bilaterally symmetrical). Since behavioral disorders arise from a combination of errant developmental trajectories as well as environmental insults, fluctuating asymmetry (as an indicator of such changes) can be used to track these disorders and hopefully serve as a diagnostic tool in clinical practice.

Some relevant publications:

Obrietan, K, M. Drinkwine and D. C. Williams 1991. Amylase, cellulase and protease activity in surface and gut tissues of Dendraster excentricus, Pisaster ochraceus and Strongylocentrotus droebachiensis (Echinodermata). Marine Biology 109: 53-57.

Taylor, R and D. C. Williams. 1995. b-glucanase activity in the seastar Pisaster ochraceus. Marine Biology 123: 735-740.

Rose James, T Nguyen, Bill Arthur, Kate Levine and D. C. Williams. 1997. Hydrolase (b-glucanase, a-amylase and protease) activity in Ariolimax columbianus (banana slug) and Arion ater (garden slug). Comparative Biochemistry and Physiology (B) 118B: 275-283.

Baird, J, J. C. Stevenson and D. C. Williams. 2000. The evolution of ADHD: A disorder of communication. Quarterly Review of Biology 75: 17-35.

Stevenson, J. C. and D. C. Williams. 2000. Parental investment, self-control, and sex differences in the expression of ADHD. Human Nature 11: 405-422.

Burton, C,  Stevenson, JC, Williams, DC, Everson, PM, Mahoney, ER and Trimble, JE (2003)  Attention Deficit Disorder (AD/HD) and fluctuating asymmetry (FA) in a college sample: an exploratory study. American Journal of Human Biology 15: 601-619