Rapid structural and epigenetic changes in polyploid and aneuploid genomes

Recent work with plants has demonstrated that genome instability can be tri ggered by a change in chromosome number arising from either whole genome du plications (polyploidy) or loss/gain of individual chromosomes (aneuploidy) . This genome instability is manifested as rapid structural and epigenetic alterations that can occur somatically or meiotically within a few generati ons after heteroploid formation. The intrinsic instability of newly formed polyploid and aneuploid genomes has relevance for genome evolution and huma n carcinogenesis, and points toward recombinational and epigenetic mechanis ms that sense and respond to chromosome numerical changes. (C) 1999 John Wi ley & Sons, Inc.