Characteristics of Interstitial (TTAGGG)n-like sequences in subtelomeric assemblies. (TTAGGG)n-like sequences detected using RepeatMasker were classified according to origin within the defined subtelomeric sequence classes (Subtelomeric repeat, blue; single-copy, yellow; boundary, magenta; none were found within Segmental Duplications), similarity to a perfect (TTAGGG)n sequence (percent divergence), the length of the (TTAGGG)n tract (x-axis), and the number of occurrences for each size class (y-axis). The short black histograms show the distribution and relative abundance of nonsubtelomeric (TTAGGG)n hits in the human genome (627 hits in 3098 Mb of DNA, including an unusual cluster of 166 hits in a 9-Mb region of Yq11.22-Yq11.23), normalized to the 20.66 Mb of subtelomeric DNA analyzed for comparison.