Genome reversion process of endopolyploidy confers chromosome instability on the descendent diploid cells

Abstract

Endotetraploidy with 4-chromatid chromosomes divides by a bipolar, 2-step meiotic-like division back to diploidy (subcells), which is chiefly achieved by co-segregation of whole genomes uncoupled from spindle participation. This study shows diploid subcell inheritance of endopolyploid-division traits: perpendicular division relative to the cytoskeleton axis, dysfunctional centromere/kinetochore regions and whole genomic separations from co-segregation. The assimilation of these traits into the innate mitotic machinery of the subcells resulted in diploid mitotic divisions that tolerated mild disturbances in cycling progression and in chromosomal distributions. The data were interpreted as demonstrating a blending together of endopolyploid and mitotic division traits with result of an endo-modified mitosis in subcell propagation. Additionally, chromosomal stickiness caused breakage in anaphase/telophase. The observations are discussed in regard to a potential for slowly developing aneuploidy with increasing genomic complexity, which is widely accepted to be the basic route in tumorigenesis.