The in vitro isolation and characterization of monosomic sublines derived from a Colcemid-treated Chinese hamster cell population.

A series of 18 sublines deficient for one or two chromosomes was isolated in vitro from a pseudodiploid Chinese hamster cell population treated appropriately with Colcemid to obtain maximal induction of aneuploidy. Chromosomes 10 and 11 were the most frequently involved and, to a lesser extent, chromosome 9 and the partially deleted 6. Since analysis of chromosome banding patterns did not reveal any evidence of chromosome rearrangement, it was concluded that entire chromosomes were absent, and thus the sublines are presumed to be monosomic. The monosomic state was quickly lost during serial culture, and the 15th passage after isolation, the monosomic cell type accounted for less than 50% of the cell population in over half the sublines. This was due to a shift in chromosome number back to 22, apparently by reacquistion of the absent chromosome, or to the appearance of tetraploidy.