The reversion to diploid cells from established triploid V79 cells

. The triploid V79 cells are stable under usual culture conditions, and do not revert to being diploid. Here, the triploid–diploid transition of triploid V79 cells has been successfully induced in suspension culture in culture dishes with untreated surfaces. The diploid cells began to appear in a population of triploid V79 cells cultured under these conditions for 4 weeks. All of the triploid cells were transformed to diploid through subsequent monolayer culture for 5 weeks. It was confirmed that the revertant diploid cells had the same characteristics as original diploid V79 cells, with respect to DNA histograms, cell volume and chromosome number. Thus, it seems that suspension culturing is an important factor that induces the triploid–diploid transition.