DNA replication in yeast is stochastic*

Largely on the basis of a simple --- perhaps too simple --- analysis of microarray-chip experiments, people have concluded that DNA replication in budding yeast (\textit{S. cerevisiae}) is a nearly deterministic process, in which the position and activation time of each origin of replication is pre-determined. In this talk, we introduce a more quantitative approach to the analysis of microarray data. Applying our new methods to budding yeast, we show that the microarray data imply a picture of replication where the timing of origin activation is highly stochastic. We then propose a physical model (the ``multiple-initiator model") to account for the observed probability distributions of origin- activation timing.