Catastrophic DNA replication in unscheduled tetraploid cells.

Unscheduled tetraploidy is a metastable state that rapidly evolves into aneuploidy. Recent findings reported by Gemble et al. demonstrate that freshly formed tetraploid cells fail to accumulate the required amounts of DNA replication factors during the first G1 phase after whole-genome duplication (WGD), culminating in genetic instability in the subsequent S phase and extensive karyotypic alterations.