title: Non-satellite repetitive human DNA families. Sequence properties and evidence for occurrence in chimpanzee DNA.
abstract: Repetitive human DNA, fractionated on CsCl gradients following hydroxyapatite isolation, contains two complex DNA fractions, the 1.703 and 1.714 DNA families (Marx, K.A., Allen, J.R. and Hearst, J.E. (1976) Biochim. Biophys. Acta 425, 129-147). Biphasic Topt profiles, obtained in DNA excess hybridizations with cRNA tracers from each DNA family, have been shown to be the likely result of a fast kinetic component hybridizing at higher temperatures (67 degrees C peak) and this fast plus a slow kinetic component both hybridizing at lower temperatures (47 degrees C peak). Equilibrium CsCl gradient DNA-cRNA hybrid distributions support previous interpretations of the sequence composition of both DNA families. That is, the fast component is a relatively undiverged repetitive sequence of recent origin, while the slow component is a highly diverged, less thermally stabile, old primate sequence. This interpretation is further strengthened by cRNA tracer hybridization experiments in chimpanzee DNA excess where the fast component appears to be absent and the slow component present.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002499:Centrifugation, Density Gradient; D004247:DNA / Q000032:analysis*; D006358:Hot Temperature; D006801:Humans; D009693:Nucleic Acid Hybridization; D002679:Pan troglodytes / Q000235:genetics*; D012313:RNA / Q000032:analysis; D014158:Transcription, Genetic
chemical_list: D012313:RNA; D004247:DNA