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Unformatted text preview: Downsyndrome is caused by aneuploidy (3 of chromosome 21) Causes: Non-disjunction during meiosis Also occurs in cancer cells during mitosis Non-disjunction during meiosis Structural Aberrations in Chromosomes Deletion a chromosome fragment breaks off and does not rejoin any chromosome Inversion a chromosome fragment breaks off and rejoins the same chromosome, but in the inverted orientation Translocation non-homologous chromosomes exchange peices Duplication unequal crossing over results in a chromosome with a region duplicated Key Points Autosomal Dominant, Autosomal Recessive, and X-linked disorders have unique patterns of inheritance Non-disjunction during meiosis can be one cause of Polyploidy or Anuploidy Aberrations can also occur within a given chromosome...
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- Spring '11