Synteny histogram of the S. meliloti chromosome in comparison to A. tumefaciens chromosomes. Red bars, syntenic genes. Framed with yellow boxes, microsyntenic regions with the A. tumefaciens (At) circular chromosome. Framed with light green boxes, microsyntenic regions with the At linear chromosome. Microsyntenic regions are denoted by letters (and numbers) in progressive order. Dark blue bars, non-syntenic genes with the At circular chromosome. Light blue bars, non-syntenic genes with the At linear chromosome. Green bars, homologs in plasmids. Gray bars, species-specific genes. White bars, homologs with other Rhizobiales chromosomes. Direction of transcription is denoted by upper (plus) or lower (minus) positions in respect to the central line. Predicted operons are denoted by red arrows. Scale in bp.