title: The structure and position of mouse centromeric heterochromatin in BrdU-labelled chromosomes and diplochromosomes stained by the pH 10.4 method.
abstract: A mouse cell line of C57Bl/6J spontaneous melanoma (clone PG 19), and a C-type virus transformed cell line (G-8 clone 124) originating from normal Balb/c mice were used in a study of the centromeric heterochromatin region of BrdU-labelled chromosomes stained by the Giemsa pH 10.4 method. Three possible explanations for the generation of compound lateral asymmetry within the centromeric heterochromatin region of the laboratory mouse are discussed: 1) inverted translocation; 2) centric fusion followed by paracentromeric fission and 3) inversion of part of the centromeric satellite DNA. These processes could be of considerable genetic and evolutionary significance. The non-random spatial position of unstained and dark stained C-bands in BrdU-labelled diplochromosomes of endoreduplicated cells can be explained as being due to the localization of the old and new DNA chains in a unineme chromatid model. The late replicating regions are shown to be located on the inside of the half-chromatid close to the axial symmetry axis of the metaphase chromosome.
mesh_terms: D000818:Animals; D001399:Azure Stains; D001973:Bromodeoxyuridine; D002460:Cell Line; D006570:Heterochromatin / Q000648:ultrastructure*; D006863:Hydrogen-Ion Concentration; D008545:Melanoma / Q000648:ultrastructure*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013194:Staining and Labeling / Q000379:methods
chemical_list: D001399:Azure Stains; D006570:Heterochromatin; D001973:Bromodeoxyuridine