Steps of nick translation- 

Low concentrations of DNase I are used to make occasional single-strand nicks in the double-stranded DNA that is intended as the gene probe.

DNA polymerase then fills in the nicks, using an appropriate dNTP, at the same time making a new nick to the 3′ side of the previous one.

TLS Online TPP Program

#Id: 6101

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6102

#Unit 3. Fundamental Processes

5-bromouracil induces transitions in both directions, A:T ↔ G:C Deamination of adenine results in A:T → G:C transitions and the deamination of cytosine produces G:C → A:T transitions, so nitrous acid induces transitions in both directions

TLS Online TPP Program

#Id: 6103

#Unit 3. Fundamental Processes

EMS causes ethylation of the bases in DNA at the 7-N and the 6-O positions. When 7-ethylguanine is produced, it base-pairs with thymine to cause G:C → A:T transitions.

TLS Online TPP Program

#Id: 6104

#Unit 3. Fundamental Processes

Base alkylation products activate error-prone DNA repair processes that introduce transitions, transversions, and frameshift mutations during the repair process

TLS Online TPP Program

#Id: 6105

#Unit 3. Fundamental Processes

In contrast to most alkylating agents, the hydroxylating agent hydroxylamine (NH2OH) has a specific mutagenic effect. It induces only G:C → A:T transitions.

TLS Online TPP Program

#Id: 6106

#Unit 3. Fundamental Processes

Thymine dimers cause mutations in two ways. (1) Dimers perturb the structure of DNA double helices and interfere with accurate DNA replication. (2) Errors occur during the cellular processes that repair defects in DNA, such as UV-induced thymine dimers To identify chemicals that are converted into mutagens in the liver, the Ames test treats potential indirect mutagens with a mixture of liver extract