No Gene interaction

Two kinds of independence

The genes at each locus were independent in their assortment in meiosis

The genes were independent in their phenotypic expression

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