[Chromosome markers of murine hybridomas]

The karyological study of 10 mouse hybridomas revealed that all cells in two hybridoma clones, as well as in two subclones isolated from the third hybridoma, contained specific clonal biarmed markers, atypical for myeloma parent cells X63.Ag8.653. The proportion of cells with additional new meta- and submetacentric markers, which were different in the cells of the same culture, reached 0.38-0.56 in some of the hybridomas under study. The above biarmed chromosomes were, probably, formed as the result of the centromeric fusions of subtelocentrics. The presence of identical new biarmed chromosomes in all cells in some hybridoma cultures could be attributed to the fact that all these cells originated from a single initial cell, already containing such marker (or markers). The results of the cytogenetic analysis may confirm the monoclonal origin of a considerable part of mouse hybridomas.