Molecular characterization of small polydisperse circular deoxyribonucleic acid from an African green monkey cell line.

Several size classes of small polydisperse circular (spc) DNA from the African green monkey cell line BSC1 have been cloned into the bacterial plasmid pBR322. Analysis of the cloned spc DNA fragments as well as total spc DNA reveals that (a) most or all cloned spc DNAs share homologies with chromosomal sequences, (b) both unique and repetitive chromosomal sequences are represented in spc DNA, (c) the repetitive sequences in spc DNA include two known major repeat families (the alpha and the Alu) as well as a third, as yet unidentified, set of interspersed repetitive sequences, and (d) the alpha-like sequences are present in an oligomeric series of circular DNA molecules within the spc DNA population. The organizational features of repetitive DNA sequence-carrying circles suggest a mechanism for their generation.