Eisen JA, Heidelberg JF, White O, Salzberg SL.

Genome Biol. 2000;1(6):RESEARCH0011. doi:10.1186/gb-2000-1-6-research0011

Evidence for symmetric chromosomal inversions around the replication origin in bacteria.

X-shaped pattern observed in line plots of pairwise comparisons between E. coli and V. cholerae, or Streptococcus or Mycobacterium species. The patterns might have been generated by inversions centered on origins and termini of replication.