Why does nondisjunction create genetic abnormality?
Nondisjunction is the failure of chromosome pairs to correctly separate during meiosis. In this case, daughter cells get either too many or too few chromosomes, and become ‘aneuploid’ (having an incorrect number of chromosomes). This can result in genetic abnormalities, such as Down’s syndrome, in which case one has three copies of Chromosome 21 (‘Trisomy 21’). Nondisjunction and aneuploidy therefore result in either too much or too little expression of critical genes.
