In biology , nondisjunction
is the failure of a chromosome to split correctly during meiosis .
This results in the production of gametes which have either more or less of the usual amount of genetic material, and is a common mechanism for trisomy or monosomy .
... A child with Down syndrome
Down syndrome (also called Down's syndrome ) encompasses a number of genetic disorders , of which trisomy 21 (a nondisjunction
) is the most representative, causing highly variable degrees of learning difficulties and physical disabilities . It is named for John Langdon-D...
... Klinefelter's syndrome is a condition caused by a chromosome abnormality in males (specifically, a nondisjunction
); sufferers have a pair of X sex chromosomes instead of just one. It is named after Harry Klinefelter , the medical researcher who first described ...
...u syndrome are not inherited, but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction
can result in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 13. If...
is the failure of chromosome pairs to separate properly during cell division. This could arise from a failure of homologous chromosomes to separate in meiosis I, or the failure of sister chromatids to separate during meiosis II or mitosis. The result of this error is a ...