Such plants must be propagated asexually. Autopolyploids are produced experimentally by treating mitotically dividing cells with colchicine . This disrupts spindle formation and results in nonsegregation of chromosomes and the consequent doubling of their number. Aneuploids are individuals that have the incorrect number of chromosomes, but not in complete sets of chromosomes. Individuals missing a single chromosome are referred to as monosomics .
Individuals having one extra chromosome are trisomics .
Aneuploids are the result of a nondisjunction occurring during nuclear division. If nondisjunction occurs during meiosis it is termed primary nondisjunction if it occurs during the first division, and secondary if it occurs during the second division. The exception to this in humans is when aneuploidy is the result of sex chromosome nondisjunction. No viable monosomies exist for autosomes in humans. Both of these syndromes have severe phenotypic effects.