Editing Genotoxicity (section)

===''in vivo'' testing===
The purpose for ''[[in vivo]]'' testing is to determine the potential of DNA damage that can affect chromosomal structure or disturb the [[mitotic spindle|mitotic apparatus]] that changes chromosome number; the factors that could influence the genotoxicity are ADME and DNA repair.  It can also detect genotoxic agents missed in ''in vitro'' tests.  The positive result of induced chromosomal damage is an increase in frequency of micronucelated PCEs.<ref name="genotoxicity.testing" />  A [[micronucleus]] is a small structure separate from the nucleus containing nuclear DNA arisen from DNA fragments or whole chromosomes that were not incorporated in the daughter cell during mitosis.  Causes for this structure are mitotic loss of acentric chromosomal fragments (clastogenicity), mechanical problems from chromosomal breakage and exchange, mitotic loss of chromosomes (aneugenicity), and apoptosis.  The micronucleus test ''in vivo'' is similar to the ''in vitro'' one because it tests for structural and numerical chromosomal aberrations in mammalian cells, especially in rats' blood cells.<ref name="genotoxicity.testing" />