A Timescale for Evolution, Population Expansion, and Spatial Spread of an Emerging Clone of Methicillin-Resistant Staphylococcus aureus
Figure 2
Increase of DNA sequence variation over the sampling time interval.
Maximum-likelihood phylogenetic tree based on sequence variation among haplotypes (a). In this tree, each haplotype has a particular distance to the root. In (b), these root-to-tip genetic distances are plotted against sampling dates. The figure illustrates a positive correlation of divergence with sampling date, and, hence, a significant increase of DNA sequence variation over the sampling time interval.