nondisjunction การใช้

• This is due to a mis-segregation ( nondisjunction ) during gametogenesis.
• Mitotic nondisjunction after conception would lead to mosaicism, and is discussed later.
• In " nondisjunction ", sister chromatids fail to separate during anaphase.
• Such Down syndrome trisomies are indistinguishable from Down syndrome trisomy created through meiotic nondisjunction.
• When the segregation is not normal, it is called " nondisjunction ".
• An error in cell division called nondisjunction can result in reproductive cells with additional chromosomes.
• Trisomy 18 ( 47, XX, + 18 ) is caused by a meiotic nondisjunction event.
• Down syndrome, Turner Syndrome, and a number of other diseases result from nondisjunction of entire chromosomes.
• Another mechanism for retaining the extra chromosome is through a nondisjunction event during meiosis II in the egg.
• Nondisjunction can occur in the meiosis I or meiosis II, phases of cellular reproduction, or during mitosis.
• The extra chromosome is retained because of a nondisjunction event during paternal or maternal meiosis I ( gametogenesis ).
• The probability of nondisjunction in human oocytes increases with increasing maternal age, presumably due to loss of cohesin over time.
• Because of the unusual cruciform pairing configuration in translocation heterozygotes, nondisjunction of homologous centromeres occurs at a measurable but low rate.
• This may be caused by a nondisjunction event in an early mitosis, resulting in a loss of a chromosome from some trisomic cells.
• The multipolar metaphase-anaphase transition occurs through an incomplete separase cycle that results in frequent nondisjunction events which amplify aneuploidy in cancer cells.
• Micronuclei form during anaphase from lagging acentric chromosome or chromatid fragments caused by incorrectly repaired or unrepaired DNA breaks or by nondisjunction of chromosomes.
• On occasion, when cells experience nondisjunction, they fail to complete cytokinesis and retain both nuclei in one cell, resulting in binucleated cells.
• Numerical errors can arise at either of the two meiotic divisions and cause the failure of a chromosome to segregate into the daughter cells ( nondisjunction ).
• Mutations of the RB1 locus in one copy of chromosome 13 are sometimes accompanied by loss of the other wild-type chromosome 13 through mitotic nondisjunction.
• In some cases, the addition of an extra Y-chromosome results from nondisjunction during cell division during a post-zygotic mitosis in early embryonic development.