Recombination events identified by Clonal Frame, using the concatenated alignment of 40 randomly selected genes, in the external branches of the L. monocytogenes strains (A) H7858, (B) F2365, (C) F6854, and (D) EGD-e. Each of the 40 genes is represented between gray vertical lines. The order of the genes (left to right) is as follow: clpX (lmo1268), lmo0343, lmo0405, pflC (lmo1407), phoP (lmo2501), lmo1436, lmo1460, lmo1537, hemC (lmo1556), ccpA (lmo1599), lmo1623, lmo1790, lmo2262, pepC (lmo2338), lmo2391, trxB (lmo2478), lmo0190, lmo0860, lmo0877, lmo1087, proA (lmo1259), lmo0992, smbA (lmo1313), lmo1401, lmo1420, opuCC (lmo1426), trpD (lmo1631), lmo1693, purK (lmo1774), lmo1825, panB (lmo1902), lmo0028, lmo2175, lmo2348, lmo2566, lmo0487, lmo0878, lmo1004, lmo1011, cbiH (lmo1199). "x" indicate substitutions inferred to have occurred in the respective branches. Red lines represent the probability for each nucleotide to have been imported by means of recombination. Values at the bottom represent the position in the alignment in kilobases.