In each cell division, the newly duplicated chromosomes must be evenly distributed between the sister cells. Errors in this process during meiosis or mitosis are equally fatal: improper segregation of the chromosome 21 during human meiosis leads to Down syndrome (Conley, Aneuploidy: etiology and mechanisms, pp 35-89, 1985), whereas in somatic cells, aneuploidy has been linked to carcinogenesis,...