Cacti computed from five primate genome alignments. (a) A neighbour joining distance tree groups the cacti into four major clades, with clade 1 (grey) covering 97% of the bases assigned to its genomic segments. The cacti in clades 2–4 (light green, blue and red) and cacti 12 and 15 (dark green) represent the remaining 2.3% and 0.7% of the genome respectively. (b) A human-centric ideogram illustrates the distribution of regions assigned to each cacti condensed into clades (1–4) and cacti 12 and 15. While clade 1 describes most of the genome, genomic regions that are better represented by cacti outside of clade 1 are distributed throughout the genome.