gene mutation, dna repair, and transposition

Copyright © 2009 Pearson Education, Inc.

Chapter 14 Lecture

Essentials of Genetics

Gene Mutation, DNA Repair, and Transposition


14.1 Mutations Are Classified in Various Ways

• Spontaneous and Induced Mutations

• Classification Based on Location of Mutation • Somatic• Germline• Autosomal• X-linked

• Mutations are also classified as dominant versus recessive


14.1 Mutations Are Classified in Various Ways

• Classification Based on Phenotypic Effects• Loss-of-function

• Gain-of-function• Morphological• Nutritional• Behavioral• Lethal• Conditional

Copyright © 2009 Pearson Education, Inc. Figure 15.1

Classification Based on Type of Molecular Change


14.2 Spontaneous Mutations Arise from Replication Errors and Base Modifications

• DNA Replication Errors

• Replication Slippage

• Tautomeric Shifts



Depurination and Deamination


Deamination



Oxidative Damage

Transposons


14.3 Induced Mutations Arise from DNA Damage Caused by Chemicals and Radiation

Base Analogs:•Compounds that can substitute for purines or pyrimidines during biosynthesis of amino acids.



Alkylating Agents:• Mustard gas is an example of an alkylating

agent that adds alkyl groups to the purine or pyrimidine of the nucleotide.


crosslinks


Acridine Dyes and Frameshift Mutations

Intercalating agents


Acridine Dyes and Frameshift Mutations

Acridine Dyes•Cause frameshift mutations.•These agents form a wedge between purines and pyrimidines of intact DNA.•This contorts the helix and can lead to deletions or insertions.


Ultraviolet Light



Ionizing Radiation

gene mutation, dna repair, and transposition

Documents