title: Heterogeneity of the ribosomal genes in mice and men.
abstract: The structures of mouse and human ribosomal DNA were studied using the restriction enzymes Eco R1 and Hind III. Individual mice or humans showed a heterogeneous pattern of restriction fragments resulting from differences in the non-transcribed spacer DNA. Six individual mice from the inbred strain CBA/H-T6 had identical patterns. The same pattern was shown by another CBA strain and by C3H. These strains were originally derived from a BALB X DBA cross made in 1920. Different patterns were found for BALB/c, C57BL and Mus poschiavinus. Cultured cells derived from C3H mice (L cells) showed a pattern quantitatively different from that of the parent strain, but two myeloma cell lines derived from BALB/c showed the same pattern as BALB/c mice. Ribosomal DNA in man is also heterogeneous. Differences were observed between human DNAs in the amounts of the different spacer classes. Studies on mouse-human cell hybrids suggest that some spacer classes are present on more than one of the five human nucleolus organizers.
mesh_terms: D000818:Animals; D002460:Cell Line; D004247:DNA / Q000032:analysis*; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004273:DNA, Neoplasm / Q000032:analysis*; D005260:Female; D006801:Humans; D006822:Hybrid Cells / Q000032:analysis; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009447:Neuroblastoma; D009690:Nucleic Acid Conformation; D010920:Placenta / Q000032:analysis; D012270:Ribosomes / Q000032:analysis*
chemical_list: D004273:DNA, Neoplasm; D004247:DNA; D004262:DNA Restriction Enzymes