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William S. Klug
Michael R. Cummings
Charlotte A. Spencer
Concepts of Genetics
Eighth Edition
Chapter 15
Gene Mutation, DNA Repair,
and Transposition
Copyright © 2006 Pearson Prentice Hall, Inc.
What’s a mutation?
Mutations Are Classified in
Various Ways
Spontaneous, Induced, and Adaptive
Mutations
Table 15-1
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Classifcation as somatic, germline, autosomal,
X-linked, recessive, dominant
“haploinsufficiency”
Classification Based on Phenotypic Effects
Loss-of-function
Gain-of-function
Morphological
Nutritional
Behavioral
Lethal
Conditional
The Spontaneous Mutation
Rate Varies Greatly among
Organisms
Deleterious Mutations in Humans
Table 15-2
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Molecular nature of mutations
base substitution
transition
transversion
Figure 15-1
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Spontaneous (and induced)
Mutations Arise from
Replication Errors and
Base Modifications
DNA Replication Errors
Replication Slippage
Tautomeric Shifts
Figure 15-2
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Figure 15-2a
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Figure 15-2b
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Figure 15-3
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Damage versus mutation
Depurination and Deamination
Figure 15-4
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Oxidative Damage
Induced Mutations Arise
from DNA Damage Caused
by Chemicals and
Radiation
Base Analogs
Figure 15-5
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Alkylating Agents
Figure 15-6
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crosslinks
Table 15-3
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Acridine Dyes and Frameshift
Mutations
Intercalating agents
Figure 15-7
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Radiation can induce mutations
Figure 15-8
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Ultraviolet Light and Thymine Dimers
Figure 15-9
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Ionizing Radiation
Figure 15-10
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Trinucleotide Repeats in Fragile X Syndrome,
Myotonic Dystrophy, and Huntington Disease
“Dynamic mutations”
Genetic anticipation
Table 15-4
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Cleary and Pearson (2005) Trends in Genetics 21:272-280
Genetic Techniques, Cell
Cultures, and Pedigree
Analysis Are All Used to
Detect Mutations
Detection in Bacteria and Fungi
Detection in Plants
Detection in Humans
Figure 15-11
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Figure 15-12
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The Ames Test Is Used to
Assess the Mutagenicity of
Compounds
Figure 15-13
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Organisms Use DNA
Repair Systems to
Counteract Mutations
Proofreading and Mismatch Repair
Postreplication Repair
SOS Response
This is not repair!
It is an example of
damage tolerance.
Figure 15-14
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SOS Response
Pol V is induced and
is error-prone.
http://www.science.siu.edu/microbiology/micr460/460%20Pages/SOS.html
Photoreactivation Repair: Reversal of
UV Damage in Prokaryotes
Figure 15-15
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Base and Nucleotide Excision Repair
Note: the sugar-phosphate
residue must be removed.
This is believed to be accomplished
by DNA pol β.
Figure 15-16
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β
Figure 15-17
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Xeroderma Pigmentosum and
Nucleotide Excision Repair in Humans
Also—defects in pol  (eta)
Figure 15-18
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Double-Strand Break Repair in Eukaryotes
Homologous recombinational repair (HR, HDR)
(particularly active in S/G2)
Nonhomologous endjoining (NHEJ)
(particularly active in G1)
Transposable Elements
Move within the Genome
and May Disrupt Genetic
Function
Insertion Sequences
Figure 15-19
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Bacterial Transposons
Often carry genes encoding antibiotic resistance.
Figure 15-20
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The Ac–Ds System in Maize
Figure 15-22
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Figure 15-22a
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Figure 15-22b
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Figure 15-22c
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Figure 15-23
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Breakage-fusion-bridge cycle
www.biologie.uni-hamburg.de/b-online/ge21/18.jpg
Mobile Genetic Elements and Wrinkled Peas:
Mendel Revisited
Copia Elements in Drosophila
Figure 15-24
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P Element Transposons in Drosophila
(transpose in germ line)
Transposable Elements in Humans
LINES and SINES
50% of genome is comprised of transposons