The Recombination Hot Spot Chi Is Embedded within Islands of Preferred DNA Pairing Sequences in the E. coli Genome  Robert B Tracy, Frédéric Chédin, Stephen C Kowalczykowski  Cell  Volume 90, Issue 2, Pages 205-206 (July 1997) DOI: 10.1016/S0092-8674(00)80328-1

Figure 1 Deviations from the Genomic Mean of A, C, G, and T at 50 Positions Surrounding the 1009 Aligned χ Sites Arrows indicate the active orientation of χ. The 99% confidence interval is shown. The most overrepresented bases at each position are indicated at the bottom. Deviations are in percent. Cell 1997 90, 205-206DOI: (10.1016/S0092-8674(00)80328-1)