Insertion time distribution for elements belonging to families unique to one genome. Analogous to Figure 4, but only for families unique to one of the two genomes. The figure shows a histogram of the number of elements with a given insertion time (horizontal axis). Values on the vertical axis are given as percent of the total number of elements. Elements unique to A. thaliana are represented by dark grey bars, and elements unique to A. lyrata by light grey bars. For A. thaliana only 363 elements belong to families unique to this species. We note that for each copy number value on the horizontal axis, the bars for both A. thaliana and A. lyrata originate at a value of zero on the vertical axis. Thus, bars are not stacked, despite their visual appearance, and do not represent the sum of copies in both species. We used this format to ensure visual clarity despite the large number of bars.