Similarity of prominent 27-mer tandem repeat regions. Self-to-self dot plot of 12 prominent tandem repeat genomic regions sharing a common 27-mer repeat unit. For example, the top row shows a 21,489 nt genomic region of CHROMOSOME_V (1,221,871–1,243,359) on the + (Watson) strand. Dots represent perfect matches of length 54 nt. For example, the dot plot for the fourth genomic region of CHROMOSOME_X (122,781–250,556) is very dense and appears black owing to the high similarity between the 54-mers. In contrast, white areas indicate discordance. Regions are grouped by sequence similarity rather than their genomic position. The green box contains four genomic regions that share the most frequent version of the 27-mer unit (5′-ACTCTCTGTGGCTTCCCACTATATTTT-3′), which we call type1. The blue box contains five genomic regions that share many copies of both type1 and another version of the 27-mer, type2 (5′-ACTCTCTGTGGCTTCCCACCATATTTT-3′), that has one (underlined) T-to-C substitution with respect to type1.
