nondisjunction

Examples of nondisjunction in the following topics:

• Disorders in Chromosome Number

  • Aneuploidy, an abnormal number of chromosomes in a cell, is caused by nondisjunction, or the failure of chromosomes to separate at meiosis.
  • Misaligned or incomplete synapsis, or a dysfunction of the spindle apparatus that facilitates chromosome migration, can cause nondisjunction.
  • The risk of nondisjunction occurring increases with the age of the parents.
  • Nondisjunction can occur during either meiosis I or II, with differing results.
  • Nondisjunction may occur during meiosis I or meiosis II.

• X-Inactivation

• Sympatric Speciation

  • Aneuploidy results when the gametes have too many or too few chromosomes due to nondisjunction during meiosis.

• Gene Duplications and Divergence

  • Aneuploidy occurs when nondisjunction at a single chromosome results in an abnormal number of chromosomes.