Between-species comparisons of the two chromosomal configurations of Bifidobacterium longum NCC2705 and of related species. Relative positions of homologous segments on sequences of configurations I (A, C) and II (B, D) of B. longum NCC2705 against S. coelicolor A3(2) (A, B) and M. tuberculosis CDC1551 (C, D). Full circles and open circles indicate pairs of homologous DNA segments that have the same, respectively the opposite orientation on the chromosome. Since the S. coelicolor A3(2) genome is linear, its origin of replication cannot be placed at position 1. Therefore, in A and B, both configurations of the B. longum genome are linearized by placing the terminus of replication at the origin of the graph. For B. longum NCC2705 in configuration I (A), the probable terminus of replication of the integrated plasmid has been chosen as the terminus of replication and placed at the origin of the graph. For the B. longum in configuration II, the maximum of the first codon position cumulative GC skew has been chosen as the terminus. On (A) and (B), position and orientation of the dnaA gene on each genome is indicated by a thick arrow. Lines represent type II regressions of direct (full line) and of indirect hits (dashed line). For each regression, the corresponding correlation coefficient is indicated.