G-banding patterns in mouse lymphoblastic leukemia L1210

The karyotype of murine lymphoblastic leukemia L1210 was studied with the use of the trypsin-Giemsa technique. The line was hypodiploid with a modal number of 38 chromosomes, including three biarmed chromosomes. All cells examined contained at least one copy of each normal chromosome with the exception of chromosome #1, in which a whole copy along with parts of the second copy was found in the marker chromsome's composition. In 65% of the cells, trisomy of chromosome #15 was observed. Nearly all cells contained only one X-chromosome. The 13 marker chromosomes that frequently occurred are described, and the presumed origin of seven of these chromosomes is described in detail. Comparison of the karyotype of murine L1210 leukemia with the karyotypes of other luekemias of the mouse showed the existence of similar chromosome aberrations. Among these aberrations, the trisomy of chromosome #15 and monosomy of the X-chromosome may be of special importance. The possible role of karyotypic changes in the genesis of the malignant phenotype of the cells is discussed.