chromosomal mutation


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Related to chromosomal mutation: gene mutation

chromosomal mutation

changes to the chromosome complement or structure of cells or organisms. There are two major types:
  1. numerical, affecting whole chromosomes (see POLYPLOID and ANEUPLOIDY), and
  2. structural, affecting genetic arrangement within chromosomes. These are usually of a fairly major type (compare POINT MUTATION) and often cause severely adverse effects. Such structural mutations are classified into various types:
  1. inversion, the rearrangement of a chromosomal segment so that it has the reverse sequence, e.g. ABCDE ----> ADCBE;
  2. deletions, the removal of a segment;
  3. duplication, the repeating of a segment either next door to the original or elsewhere along the chromosome;
  4. translocation, the exchange of segments between nonhomologous chromosomes.