Fig. 4

Transposon-triggered inversions. In each panel, the second row indicates the pair of transposon copies, which triggered the inversion, and their genomic distance. Thin arrows in the 3^rd row indicate transposons with target duplications drawn as colored triangles. The corresponding target duplication sequences are shown in the 1^st row. In the 4^th row, protein-coding genes are shown by thick filled arrows with an indication of the integer part of the ordered locus tag (the term “Asalp_” was omitted for space reasons). For protein-coding genes, which are split into two fragments, the N-terminal fragment is labeled “N”, the C-terminal labeled “C” (see also Additional file 1: Table S4). Additional illustrations, which lend further support for the interpretation as a genome inversion, are panel-specific. a The adjacent protein-coding genes and their genomic clustering are illustrated for A. salmonicida subsp. salmonicida strain A449 with highly conserved sequences specified by identical coloring. b One of the transposon copies (ISAs19_PB) belongs to a complex transposon conglomerate as indicated by additional transposons in the 2^nd row (see also Additional file 1: Fig. S3 B). This transposon has targeted a protein-coding gene, which, after inversion, is split into two genomically distant fragments (Asalp_30800 and Asalp_20650). These two fragments together are the full-length homolog of VC_A0374 from Vibrio cholerae with 51% sequence identity. c One transposon copy of ISAs27 has targeted another transposon (Aersa_Kpn10), which is split into two fragments as indicated in the 2^nd row. The two fragments combine to a single complete element with just an internal insertion of one target duplication. The other transposon copy of ISAs27 has targeted a protein-coding gene, which, after inversion, is split into two genomically distant fragments (Asalp_21800 and Asalp_20620). These fragments are together a full-length homolog of AHA_2662 from Aeromonas hydrophila with 95% sequence identity. d One of the transposon copies has targeted a protein-coding gene, which, after inversion, is split into two genomically distant fragments (Asalp_39690 and Asalp_39270). These fragments are together a full-length homolog of ATN88_05900 from Enterovibrio coralii with 44% sequence identity. One of the elements has targeted a transposon (Aersa_IS5), which is incomplete. The targeting element was probably affected by a subsequent rearrangement so that the residual part of the targeted transposon is absent and a 2^nd target duplication is not encountered