<Ul> <Li> Intercalating agents, such as ethidium bromide and proflavine, are molecules that may insert between bases in DNA, causing frameshift mutation during replication . Some such as daunorubicin may block transcription and replication, making them highly toxic to proliferating cells . </Li> </Ul> <Li> Intercalating agents, such as ethidium bromide and proflavine, are molecules that may insert between bases in DNA, causing frameshift mutation during replication . Some such as daunorubicin may block transcription and replication, making them highly toxic to proliferating cells . </Li> <P> Many metals, such as arsenic, cadmium, chromium, nickel and their compounds may be mutagenic, but they may act, however, via a number of different mechanisms . Arsenic, chromium, iron, and nickel may be associated with the production of ROS, and some of these may also alter the fidelity of DNA replication . Nickel may also be linked to DNA hypermethylation and histone deacetylation, while some metals such as cobalt, arsenic, nickel and cadmium may also affect DNA repair processes such as DNA mismatch repair, and base and nucleotide excision repair . </P> <Ul> <Li> Transposon, a section of DNA that undergoes autonomous fragment relocation / multiplication . Its insertion into chromosomal DNA disrupts functional elements of the genes . </Li> <Li> Virus--Virus DNA may be inserted into the genome and disrupts genetic function . Infectious agents have been suggested to cause cancer as early as 1908 by Vilhelm Ellermann and Oluf Bang, and 1911 by Peyton Rous who discovered the Rous sarcoma virus . </Li> <Li> Bacteria--some bacteria such as Helicobacter pylori cause inflammation during which oxidative species are produced, causing DNA damage and reducing efficiency of DNA repair systems, thereby increasing mutation . </Li> </Ul>

What is the term for chemicals capable of producing genetic mutations