For the centromeres that were similar to B73 among the inbreds, we measured the center of mass of CENH3 enrichment by treating each centromere as a series of discrete 20-kb loci and by multiplying the value for CENH3 enrichment by the chromosomal position of each locus. We defined “shift” to be the difference between the center of mass for a particular sample and the average center of mass for the whole group. “Estimated % B73” indicates the total amount of genomic DNA contributed by B73 during the production of each inbred (Nelson et al. 2008). In addition to the B73 and nine of the B73-related inbreds already discussed (PHW17 was excluded because neither its centromere 2 nor centromere 5 are B73-like), we included three other B73 sample populations. Two of the B73 samples had been separated from the first B73 (“reference”) by two generations of self-crosses (“selfed sibling 1” and “selfed sibling 2”), and one B73 had been separated from the first by an unknown number of generations (“distant kin”; the last common ancestor is documented as more than six generations earlier). For a high-resolution view of CENH3 distributions across centromeres, see Figure 4.