Potential for evolving Cit⁺ mapped onto phylogeny.

<p>Phylogeny of isolates from the LTEE population including 20 new clones sequenced for this study to provide better resolution of the timing of mutations on the lineage leading to Cit⁺ (names in italics). In order to identify changes in the degree of potentiation due to mutations, we mapped the results of the P_<i>rnk</i><i>-citT</i> knock-in assay onto this phylogenetic tree. Colored symbols reflect the Cit⁺ to Cit⁻ relative fitness measured for those strains. The ancestor and 61 evolved isolates were used to construct this phylogenetic tree (<b><a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007348#pgen.1007348.s006" target="_blank">S1 Table</a></b>). Two clones isolated at 50,000 generations are not shown. Two strains that evolved citrate utilization in replay experiments under the LTEE conditions in a previous study [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007348#pgen.1007348.ref007" target="_blank">7</a>] are marked with plus signs (++), and three strains that had evolved alleles added or removed during strain construction as described in <b><a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1007348#pgen.1007348.s007" target="_blank">S2 Table</a></b> are starred (*).