Genotoxicity encompasses all the potential means by which the genetic material of higher organisms may be damaged, with the potential for resulting serious consequences. Most forms of genotoxicity are expressions of mutagenicity-the induction of DNA damage and other genetic alterations, with binding to and changes in one or a few of DNA base pairs (gene mutations), Elastogenicity that is gross changes in chromosomal structure (i.e., chromosomal aberrations) or in chromosome numbers represents a different class of genotoxic changes, for which practical thresholds of effect are identifiable.