RESTRICTION SITE PERIODICITIES IN HIGHLY REPETITIVE DNA OF PRIMATES

Highly repeated DNA sequences from 3 Old World primate groups were compared using restriction endonucleases. Baboons [Papio], macaques [Macaca] and mangabeys [Cercocebus] share a 340 base-pair [bp], tandemly repeated DNA that is cut once by BamHI. The several species of guenons, including the African green monkey [Cercopithecus aethiops], possess a related 170 bp, tandemly organized sequence distinguished by the feature of being cut once by HindIII, MboII or HphI. The tandemly repeated DNA of the colobus monkey [Colobus] is based on a monomer length of 680 bp, being cut once by BamHI or EcoRI. All 3 highly repeated DNA have a monomer length of 170n bp, where n = 1, 2 or 4. The 340 and 680 bp repeated DNA contain an internal 170 bp periodicity, especially with respect to the HindIII cleavage site, and to several other enzymes that characterize each repeated sequence. The 170 bp length is called the fundamental unit. The 3 repeated DNA are more conserved in the region around the HindIII site and are more divergent elsewhere in the sequence. All seven 170 bp fundamental units were related to one another, judging from the overall similarities of the maps of restriction endonuclease cleavage sites. The highly repeated DNA from baboons and guenons [Cercopithecus] are related enough to cross-hybridize at relaxed criteria (60.degree. C in 0.12 M Na+), but neither hybridizes to repeated colobus DNA under this condition. Highly repeated sequences in primates form a common library descended from a ancestral sequence, with 170 bp composing the fundamental unit of library members. Occasionally, a member of the library is amplified, creating a newly amplified family. In Old World monkeys the most recent amplification just preceded active speciation.