[Karyotype analysis of clone L929 murine fibroblasts by using differential chromosome staining]

Karyological analysis of mouse fibroblasts L929 has been carried out using the differential staining of chromosomes (44-58% of the total chromosome number), and their derivatives, i.e. markers of the particular clone. Normal, non-rearranged chromosomes are mainly present in 1-3 copies, while the markers are available as a single copy only. The frequency of occurrence of diverse chromosomes differs from cell to cell, the total number of chromosomes in the cells being not constant. The modal class consists of 62-64 chromosomes. Two new chromosome markers were found after a repeated karyological analysis one year after the cultivation of cells under the standard conditions. A possible role of some chromosome aberrations in the process of transformation of mouse fibroblasts is discussed. The particular attention is given to alteration of chromosome 15.