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crossing over

The reciprocal exchange of segments at corresponding positions along pairs of homologous chromosomes by symmetrical breakage and crosswise rejoining forming cross-over sites that are resolved during chromosome segregation. Crossing-over typically occurs during meiosis but it may also occur in the absence of meiosis, for example, with bacterial chromosomes, organelle chromosomes, or somatic cell nuclear chromosomes.
Concept Schemes:
Entry Terms:
  • chiasma frequency
  • sister chromatid exchange
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RDF/XMLCreated 2006-01-19, last modified 2017-08-17