E-painting results for chromosomes HSA 10, HSA 12 and HSA 22. The stippled red lines indicate regions of primate-specific breakpoints. Black lines within the ideograms represent the positions of breaks in synteny which were probably caused by inversions. Unique colour codes link the HSA12q distal segment (Mb 107.03–132.00) and the central 22q segment (Mb 17.14–30.83), representing the smallest eutherian chromosome [10, 12] (12b-22b in Figure 2), as well as the segments 12pter-12q (Mb 0–106.67), 22q proximal (Mb 14.4–17.03), and 22q distal (Mb 31.11–49.60) representing a medium-sized eutherian chromosome (12a-22a in Figure 2). In dog and cow, the HSA10p orthologous segment (Mb 0–37.45) bears a colour code that is different from the HSA12 and HSA22 orthologues and hence does not provide any evidence for an evolutionary association. However, the shared synteny on opossum chromosome 8 confirms previously performed chromosome painting data [11, 56, 60], strongly suggesting common ancestral HSA10p/12pq/22q orthology. The E-painting data from the murids are not informative in this regard.