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Concepts of Genetics
Ninth Edition
Klug, Cummings, Spencer, Palladino
Chapter 16
Gene Mutation and DNA Repair
Copyright
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Education,
Inc.
Copyright
2009 Pearson
Education,
Inc.
What’s a mutation?
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16.1 Mutations Are Classified in
Various Ways
16.1.1 Spontaneous and Induced Mutations
16.1.2 The Luria-Delbruck Fluctuation Test:
Are Mutations Spontaneous or
Adaptive?
16.1.1.1 Hypothesis 1: Adaptive Mutation.
16.1.1.2 Hypothesis 2: Spontaneous
Mutation.
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Table 16.2
16.1 Mutations Are Classified in Various
Ways
16.1.3 Classification Based on Location of Mutation
Somatic, germline, autosomal, X-linked
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Mutations are also classified as
dominant versus recessive
“Haploinsufficiency” also is seen.
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16.1 Mutations Are Classified in Various
Ways
Classification Based on Phenotypic Effects
Loss-of-function
Gain-of-function
Morphological
Nutritional
Behavioral
Lethal
Conditional
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Table 16.1
Classification Based on Type of Molecular Change
base substitution
transition
transversion
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Figure 16.1
16.2 Spontaneous Mutations Arise from
Replication Errors and Base
Modifications
16.2.1 DNA Replication Errors
16.2.2 Replication Slippage
16.2.3 Tautomeric Shifts
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Figure 16.2
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Figure 16.2a
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Figure 16.2b
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Figure 16.3
Damage versus mutation
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16.2
Spontaneous Mutations Arise from
Replication Errors and Base
Modifications
16.2.4
Depurination and Deamination
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Deamination
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Figure 16.4
16.2 Spontaneous Mutations Arise from
Replication Errors and Base
Modifications
16.2.5 Oxidative Damage
16.2.6 Transposons
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16.3
Induced Mutations Arise from DNA
Damage Caused by Chemicals and
Radiation
16.3.1 Base Analogs
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Figure 16.5
16.3
Induced Mutations Arise from DNA
Damage Caused by Chemicals and
Radiation
16.3.2 Alkylating Agents and Acridine Dyes
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Example of alkylation
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Figure 16.6
crosslinks
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Table 15-3
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Acridine Dyes and Frameshift
Mutations
Intercalating agents
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A couple of intercalating agents
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Figure 15-7
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16.3 Induced Mutations Arise from DNA
Damage Caused by Chemicals and
Radiation
16.3.3 Ultraviolet Light
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Figure 16.7
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Figure 16.8
16.3
Induced Mutations Arise from DNA
Damage Caused by Chemicals and
Radiation
16.3.4 Ionizing Radiation
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Figure 16.9
16.4 Genomics and Gene Sequencing
Have Enhanced Our Understanding of
Mutations in Humans
16.4.1 ABO Blood Types (IO= frameshift)
16.4.2 Muscular Dystrophy (Duchenne vs Becker)
16.4.3 Fragile X Syndrome, Myotonic Dystrophy, and
Huntington Disease
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Trinucleotide Repeats in Fragile X
Syndrome, Myotonic Dystrophy, and
Huntington Disease
“Dynamic mutations”
Genetic anticipation
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Table 15-4
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Cleary and Pearson (2005) Trends in Genetics 21:272-280
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16.5 The Ames Test Is Used to Assess the
Mutagenicity of Compounds
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Figure 16.10
16.6 Organisms Use DNA Repair Systems
to Counteract Mutations
Proofreading and Mismatch Repair
Postreplication Repair
The SOS Repair System
(SOS Response)
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This is not repair!
It is an example of
damage tolerance.
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Figure 16.11
Response
SOSSOS
response
in bacteria
Pol V is induced and
is error-prone.
http://www.science.siu.edu/microbiology/micr460/460%20Pages/SOS.html
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16.6 Organisms Use DNA Repair Systems
to Counteract Mutations
16.6.3 Photoreactivation Repair: Reversal of UV
Damage
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Figure 16.12
16.6
Organisms Use DNA Repair Systems
to Counteract Mutations
16.6.4 Base and Nucleotide Excision Repair
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Figure 16.13
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Figure 16.14
16.6 Organisms Use DNA Repair Systems
to Counteract Mutations
16.6.5 Nucleotide Excision Repair and Xeroderma
Pigmentosum in Humans
Also—defects in pol  (eta)
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Figure 16.15
16.6 Organisms Use DNA Repair Systems
to Counteract Mutations
16.6.6 Double-Strand Break Repair in Eukaryotes
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There are other pathways for
DSB repair via homologous
recombination.
This type of repair is
accurate, and is prominent in
late S/G2 .
DSBs can also be repaired
via nonhomologous endjoining, which is error-prone
and is prominent during G1.
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Figure 16.16
16.7 Geneticists Use Mutations to Identify
Genes and Study Gene Function
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