Marker Frequency distributions: exponential growth versus stationary phase for S. solfataricus (courtesy of Magnus Lundgren). Here DNA from S. solfataricus cells in exponential phase was compared to DNA from cells in stationary phase. Cells that just have begun growing have more copies of genes at or close to a DNA replication site than DNA further from the replication start site. Therefore genes close to a replication start site will have a higher ratio than genes not close to such a site and this is seen as a peak in the figure. The figure has three clear peaks, showing that S. solfataricus has 3 origins of replication; each peak is located near a predicted cdc6 site.
