DNA Replication [1, 2]

In higher organisms, DNA replication occurs at many places simultaneously. Recently, experiments have allowed one to observe individual replicated and non-replicated domains at various times during the replication process. We have constructed a stochastic model of the replication process that allows us to extract information about the initiation of replication domains and their subsequent behaviour. Our current work focusses on several aspects:

• General modelling issues
• Yeast replication (in collaboration with Nick Rhind)
• Replication in cancer cells (in collaboration with Fabrizio d'Adda di Fagagna and Genomic Vision; funded by the Human Frontier Science Program, HFSP)
• Single-cell experiments

DNA conductivity

The electrical conductivity of DNA is interesting for many reasons, both fundamental and applied. We have been developing techniques involving conducting-probe AFM and break junctions to probe the electrical properties of DNA. More to come!

AFM techniques [1, 2]

The atomic force microscope has proven to be one of the most powerful and useful tools in nanotechnology. One limitation is that current commercial instruments are slow, with typical line-scan rates of 10 Hz or less. We are exploring various ways to speed up this rate. Projects include:

• Novel applications of control theory for faster AFM
• Faster force-distance curves

FCS and variants

For our teaching program, we developed a fluorescence correlation spectrometer for measuring diffusion constants. We are currently exploring extensions to novel ways to trap single molecules based on force feedback.