Progress has recently been made towards the development of an accurate
theoretical model of DNA structure and motions on the basis of molecu
lar dynamics computer simulations. Recent quantitative comparisons bet
ween calculated properties with those observed in crystal structure de
terminations and nuclear magnetic resonance experiments allow improvem
ent of modelling techniques. Current issues in molecular dynamics meth
odology, particularly truncation of potentials, are discussed, followe
d by a survey of results from in vacuo and in aquo treatments of solve
nt. The results of recent in aquo DNA trajectories extended into the n
anosecond regime, together with a comparison of calculated and observe
d axis bending behavior, close the gap between the timescale of molecu
lar dynamics simulation and NMR techniques. Examples illustrating the
analysis of DNA molecular dynamics simulations are included and discus
sed.