Summary of theories of the mechanisms of chromosomal aberrations: A, ‘classic’ breaks theory; B, ‘mis-repair of breaks’ theory; C, ‘repair-created breaks’ theory. Adapted from Bignold. There is not one all encompassing method by which<unk> s damage chromosomal DNA, instead different<unk> s have unique ways they interact with DNA, or DNA associated proteins, and disrupt normal function. Broadly these different types of<unk> ic activity can be organized into three classes: ‘classic’ breaks theory; ‘mis-repair of breaks’ theory and ‘repair-created breaks’ theory. It may not always be known how a<unk>  causes chromosomal damage. Radiation was the earliest known<unk>  that caused direct DNA damage, following the classic breaks theory. DNA is frequently damaged and there are many DNA repair pathways that combat this, but repair does not always work perfectly resulting in mistakes (called a misrepair). A widely studied class of<unk> s are alkylating agents which do not break DNA at all, but instead form DNA adducts, and these have often eluded the common theories for DNA breaks leading to misrepair. The final theory encompasses<unk> s that do not interact with DNA but instead impair DNA synthesis proteins or DNA repair proteins causing damage to occur through loss of normal function of the protein.<unk>  damage in certain areas of the chromosome can lead to instability, such as loss or damage to telomeres. Studies have shown that rat cells that were exposed to chemical<unk> s express telomeric irregularities in function and can remain for several cell generations after treatment has been attempted.
Clastogen
Immunoevasin
Endrin
Tetanospasmin
Anordrin
Dieldrin
Prohormone
Serpin