498Chapter 15 •Large-Scale Chromosomal ChangesABCEDCCDEthe two segments are adjacent to each other (a tandemduplication), as in this duplication of segment C:ANormal sequenceParacentricPericentricFDABBCEDFADCBEFHowever, the duplicate segment can end up at a differ-ent position on the same chromosome, or even on a dif-ferent chromosome.The following sections consider the properties ofthese balanced and unbalanced rearrangements.InversionsInversions are of two basic types. If the centromere isoutside the inversion, the inversion is said to be paracen-tric.Inversions spanning the centromere are pericentric.5´ 3´3´5´APBC DBreakpointsbetweengenesNormal sequence5´ 3´3´ 5´P3´5´3´5´ 3´5´3´5´PPPPPPBreaks in DNA5´ 3´3´5´PCBD3´5´3´5´3´5´3´5´ PPPInverted alignment5´3´3´ 5´PPPPJoining of breaks to complete inversionInversionInversionInversion5´3´3´ 5´P“C”“”B PPP
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