title: Genetic studies in NZB mice. II. Hyperdiploidy in the spleen of NZB mice and their hybrids.
abstract: The presence of hyperdiploidy was studied in New Zealand black (NZB) mice and the progeny of NZB X DBA/2 crosses and backcrosses. Hyperdiploidy was observed in the spleens of a majority of NZB mice but not in DBA/2 mice at 1 year of age. In crosses of NZB with the DBA/2 strain, hyperploidy was observed only in backcrosses to NZB. Hyperdiploidy appeared to be determined by a recessivley inherited trait and was not related to the presence of other immunological abnormalities, including splenomegaly, hypergammaglobulinemia, and spontaneous antibodies cytotoxic for T cells and reactive with single-stranded DNA. Abnormal cells were not present in Concanavalin A-stimulated 48-h spleen cultures. There was no difference in the in vitro sister chromatid exchange rate between the autoimmune NZB strain and the non-autoimmune DBA/2 strain. Identification of NZB chromosomes by banding analysis showed that chromosomes 15 and 17 were frequently present in more than two copies in hyperdiploid spleen cells. NZB chromsomes also had reduced C-banding in an autosomal pair. These studies indicate that chromosomal abnormalities which occur in NZB mice may be useful as genetic and cytogenetic markers.
mesh_terms: D000367:Age Factors; D000818:Animals; D001323:Autoantibodies / Q000032:analysis; D002478:Cells, Cultured; D002842:Chromatids / Q000648:ultrastructure; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D004171:Diploidy; D005260:Female; D006570:Heterochromatin / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008814:Mice, Inbred NZB / Q000235:genetics*; D009929:Organ Size; D013154:Spleen / Q000648:ultrastructure*
chemical_list: D001323:Autoantibodies; D006570:Heterochromatin