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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
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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
Classification Based on Type of Molecular Change Figure 15.1
14.2 Spontaneous Mutations Arise from Replication Errors and Base Modifications • DNA Replication Errors • Replication Slippage • Tautomeric Shifts
14.2 Spontaneous Mutations Arise from Replication Errors and Base Modifications • Depurination and Deamination
Deamination Figure 15.4
14.2 Spontaneous Mutations Arise from Replication Errors and Base Modifications • 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.
15.3 Induced Mutations Arise from DNA Damage Caused by Chemicals and Radiation • Alkylating Agents: • Mustard gas is an example of an alkylating agent that adds alkyl groups to the purine or pyrimidine of the nucleotide.
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 Figure 15.7
15.3 Induced Mutations Arise from DNA Damage Caused by Chemicals and Radiation • Ionizing Radiation
Ionizing Radiation Figure 15.9