Mechanisms of spontaneous and induced heteroploidization and polyploidization.

Mechanisms of heteroploidization and polyploidization were studied in tissue cultures, using various methods and cell lines. In untreated populations cells with different chromosome number are formed by mitotic non-disjunction. Mononuclear polyploid cells are formed by repeated DNA synthesis (endoreduplication) and polynuclear giant cells by postmitotic fusion of the daughter cells. These phenomena occur more frequently in cell populations treated with cystostatic drugs. Most polyploid cells are not viable.