David majored in Molecular and Cell Biology at Texas A&M University, where he became fascinated that macromolecular structures could explain how their components worked.  He did research in biochemistry as an undergraduate with Prof. Ry Young at Texas A&M and summer internships at Princeton and Biogen.  As a graduate student with Stephen C. Harrison, David used structural biology and biochemistry to understand how perhaps the ultimate DNA-binding protein assembly - the kinetochore - binds to a special nucleosome at the centromere to effect chromosome segregation during cell division.