Numerical<unk>  is a high rate of either gain or loss of whole chromosomes; causing aneuploidy. Normal cells make errors in chromosome segregation in 1% of cell divisions, whereas cells with<unk>  make these errors approximately 20% of cell divisions. Because aneuploidy is a common feature in tumour cells, the presence of aneuploidy in cells does not necessarily mean<unk>  is present; a high rate of errors is definitive of<unk> . One way of differentiating aneuploidy without<unk>  and<unk> -induced aneuploidy is that<unk>  causes widely variable (heterogeneous) chromosomal aberrations; whereas when<unk>  is not the causal factor, chromosomal alterations are often more clonal. Structural<unk>  is different in that rather than whole chromosomes, fragments of chromosomes may be duplicated or deleted. The rearrangement of parts of chromosomes (translocations) and amplifications or deletions within a chromosome may also occur in structural<unk> .
Chromosome instability
Human genetic enhancement
Sex chromosome anomalies
Developmental toxicity
Antineoplastic resistance
Chromosomal translocation
Germline mutation
Aneuploidy