<P> Induced mutations on the molecular level can be caused by: </P> <Ul> <Li> Chemicals <Ul> <Li> Hydroxylamine </Li> <Li> Base analogs (e.g., Bromodeoxyuridine (BrdU)) </Li> <Li> Alkylating agents (e.g., N - ethyl - N - nitrosourea (ENU)). These agents can mutate both replicating and non-replicating DNA . In contrast, a base analog can mutate the DNA only when the analog is incorporated in replicating the DNA . Each of these classes of chemical mutagens has certain effects that then lead to transitions, transversions, or deletions . </Li> <Li> Agents that form DNA adducts (e.g., ochratoxin A) </Li> <Li> DNA intercalating agents (e.g., ethidium bromide) </Li> <Li> DNA crosslinkers </Li> <Li> This figure depicts the following processes of transcription, splicing, and translation of a eukaryotic gene . Oxidative damage </Li> <Li> Nitrous acid converts amine groups on A and C to diazo groups, altering their hydrogen bonding patterns, which leads to incorrect base pairing during replication . </Li> </Ul> </Li> <Li> Radiation <Ul> <Li> Ultraviolet light (UV) (non-ionizing radiation). Two nucleotide bases in DNA--cytosine and thymine--are most vulnerable to radiation that can change their properties . UV light can induce adjacent pyrimidine bases in a DNA strand to become covalently joined as a pyrimidine dimer . UV radiation, in particular longer - wave UVA, can also cause oxidative damage to DNA . </Li> <Li> Ionizing radiation . Exposure to ionizing radiation, such as gamma radiation, can result in mutation, possibly resulting in cancer or death . </Li> </Ul> </Li> </Ul> <Li> Chemicals <Ul> <Li> Hydroxylamine </Li> <Li> Base analogs (e.g., Bromodeoxyuridine (BrdU)) </Li> <Li> Alkylating agents (e.g., N - ethyl - N - nitrosourea (ENU)). These agents can mutate both replicating and non-replicating DNA . In contrast, a base analog can mutate the DNA only when the analog is incorporated in replicating the DNA . Each of these classes of chemical mutagens has certain effects that then lead to transitions, transversions, or deletions . </Li> <Li> Agents that form DNA adducts (e.g., ochratoxin A) </Li> <Li> DNA intercalating agents (e.g., ethidium bromide) </Li> <Li> DNA crosslinkers </Li> <Li> This figure depicts the following processes of transcription, splicing, and translation of a eukaryotic gene . Oxidative damage </Li> <Li> Nitrous acid converts amine groups on A and C to diazo groups, altering their hydrogen bonding patterns, which leads to incorrect base pairing during replication . </Li> </Ul> </Li> <Ul> <Li> Hydroxylamine </Li> <Li> Base analogs (e.g., Bromodeoxyuridine (BrdU)) </Li> <Li> Alkylating agents (e.g., N - ethyl - N - nitrosourea (ENU)). These agents can mutate both replicating and non-replicating DNA . In contrast, a base analog can mutate the DNA only when the analog is incorporated in replicating the DNA . Each of these classes of chemical mutagens has certain effects that then lead to transitions, transversions, or deletions . </Li> <Li> Agents that form DNA adducts (e.g., ochratoxin A) </Li> <Li> DNA intercalating agents (e.g., ethidium bromide) </Li> <Li> DNA crosslinkers </Li> <Li> This figure depicts the following processes of transcription, splicing, and translation of a eukaryotic gene . Oxidative damage </Li> <Li> Nitrous acid converts amine groups on A and C to diazo groups, altering their hydrogen bonding patterns, which leads to incorrect base pairing during replication . </Li> </Ul>

What is another group of mutations that may have important consequences for gene expression