chromosomes mutation

• what is chromosomes mutations?

  mutations in the number of chromosomes that arise spontaneously by chromosome non-disjunction during meiosis
• what are the two forms of non-disjunction ?

  1. changes in the whole sets of chromosomes (polyploidy)
  2. changes in the number of individual chromosomes( aneuploidy )
• what is polyploidy ?

  changed in the whole set of chromosomes that occur when organsims have three or more sets of chromosomes rather than the usual two
• where does polyploidy mainly occur?

  plants
• what is non-disjunction?

  when chromosomes or chromatids do not split equally during anaphase
• what is aneuploidy

  changed in the number of individual chromosomes this non-disjunction results in a gamete having one or fewer chromosomes
• what happens when non-disjunction occurs during meiosis I ?

  homologous chromosomes are stuck together and dont split during independant segregation
• what happens when non-disjunction occurs during meiosis II ?

  occurs when sister chromatids dont seperate