a The 7A centromere. The top panel shows cross-over counts from an analysis of 900 lines (only cross-overs from 465 lines shown; see Additional file 1) of a MAGIC population (10 Mb bin size) across the entire chromosome and identifies a region of zero recombination traditionally associated with the centromere. The second panel shows this region is the primary location of the Cereba TEs that define wheat centromeres. Within this region we also identified a compact cluster of Tai 1 sequence elements shown in red. The third panel indicates the location of the breakpoints that generated the 7AS and 7AL telosomes, and the bottom panel shows the Gydle islands (sequences in orange) and Bionano maps (7AS in green, 7AL in blue) for this region tiling the IWGSC RefSeq v1.0 (gray) from 340 Mb to 370 Mb. The break in both the Gydle and Bionano maps in the 349 Mb region is referenced in the text as well as Fig. 6a as a possible location of CENH3 binding sites. b The 7A centromere aligned to rice chromosome 8. Lines indicate syntenic genes, with conserved gene models between the two centromere regions highlighted in blue. Equivalent locations of the CENH3 binding sequences shown on the right and left sides. The CENH3 plot for the rice 8 centromere (right side) was modified from Yan et al.