Age determination of Xiao, type I, type II, and type III DAs. Top: The primer pairs, indicated as paired arrows, flanked the junctions unique to each type of Xiao or DA as labeled (see the main text for details). "SES" represents the conserved flanking element of "SATR-HERVE-SATR", where SATR represents satellite sequences SATR1 and SATR2. "16p-1", "16p-2", "21q", and "8p" inside the changing core represent the four sequence fragments from the donor loci on chromosomes 16p, 21q, and 8p, respectively. Bottom: Using primers indicated above, each type of duplicon was amplified from genomic DNA samples of the 12 primates: A: human or Homo sapiens (HSA); B: chimp or Pan troglodytes (PTR); C: bonobo or Pan paniscus (PPA); D: gorilla or Gorilla gorilla (GGO); E: orangutan or Pongo pygmaeus (PPY); F: gibbon or Hylobates leucogenys (HLE); G: siamang or Hylobates syndactylus (HSY); H: rhesus macaque or Macaca mulatta (MMU); I: pigtail macaque or Macaca nemestrina (MNE); J: tamarin or Saguinus labiatus (SLA); K: spider monkey or Ateles geoffroyi (AGE); and L: lemur or Lemur catta (LCA). The faint band for the 16p-1/21q junction in MMU (lane H of the 3rd gel image on the right) was likely due to nonspecific amplification because the result with another set of primers was negative (repeated multiple times). Additionally, we did not find this junction in the released rhesus macaque genomic sequences . The leftmost and the rightmost lanes are 100 bp and 1 kb ladders respectively (size indicated in Kb).