copyright © 2009 pearson education, inc. chapter 15 lecture concepts of genetics tenth edition gene...
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Copyright © 2009 Pearson Education, Inc.
Chapter 15 Lecture
Concepts of GeneticsTenth Edition
Gene Mutation, DNA Repair, and Transposition
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What’s a mutation?
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15.1 Mutations Are Classified in Various Ways
Spontaneous and Induced Mutations
The Luria-Delbruck Fluctuation Test: Are Mutations Spontaneous or Adaptive?
Hypothesis 1: Adaptive Mutation.Hypothesis 2: Spontaneous Mutation.
Copyright © 2009 Pearson Education, Inc. Table 15.2
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15.1 Mutations Are Classified in Various Ways
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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15.1 Mutations Are Classified in Various Ways
Classification Based on Phenotypic Effects
Loss-of-functionGain-of-functionMorphologicalNutritionalBehavioralLethalConditional
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Classification Based on Type of Molecular Change
base substitutiontransitiontransversion
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15.2 Spontaneous Mutations Arise from Replication Errors and Base Modifications
DNA Replication Errors
Replication Slippage
Tautomeric Shifts
Copyright © 2009 Pearson Education, Inc. Figure 15.2
Copyright © 2009 Pearson Education, Inc. Figure 15.2a
Copyright © 2009 Pearson Education, Inc. Figure 15.2b
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Damage versus mutation
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15.2 Spontaneous Mutations Arise from Replication Errors and Base Modifications
Depurination and Deamination
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Deamination
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15.2 Spontaneous Mutations Arise from Replication Errors and Base Modifications
Oxidative Damage
Transposons
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15.3 Induced Mutations Arise from DNA Damage Caused by Chemicals and Radiation
Base Analogs
Copyright © 2009 Pearson Education, Inc. Figure 15.5
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15.3 Induced Mutations Arise from DNA Damage Caused by Chemicals and Radiation
Alkylating Agents and Acridine Dyes
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Example of alkylation
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crosslinks
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Acridine Dyes and Frameshift Mutations
Intercalating agents
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A couple of intercalating agents
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15.3 Induced Mutations Arise from DNA Damage Caused by Chemicals and Radiation
Ultraviolet Light
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15.3 Induced Mutations Arise from DNA Damage Caused by Chemicals and Radiation
Ionizing Radiation
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15.4 Single-Gene Mutations Cause a Wide Range of Human Diseases
Copyright © 2009 Pearson Education, Inc. Table 15.3
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Section 15.4
Table 15.4
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Trinucleotide Repeats in Fragile X Syndrome, Myotonic Dystrophy, and Huntington Disease
“Dynamic mutations”
Genetic anticipation
Copyright © 2009 Pearson Education, Inc.Table 15-4 Copyright © 2006 Pearson Prentice Hall, Inc.
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Cleary and Pearson (2005) Trends in Genetics 21:272-280
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15.5 Organisms Use DNA Repair Systems to Counteract Mutations
Proofreading and Mismatch Repair
Postreplication Repair
The SOS Repair System
(SOS Response)
Copyright © 2009 Pearson Education, Inc. Figure 15.11
This is not repair!It is an example ofdamage tolerance.
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SOS Response
http://www.science.siu.edu/microbiology/micr460/460%20Pages/SOS.html
Pol V is induced andis error-prone.
SOS response in bacteria
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15.5 Organisms Use DNA Repair Systems to Counteract Mutations
Photoreactivation Repair: Reversal of UV Damage
Copyright © 2009 Pearson Education, Inc. Figure 15.12
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15.5 Organisms Use DNA Repair Systems to Counteract Mutations
Base and Nucleotide Excision Repair
Copyright © 2009 Pearson Education, Inc. Figure 15.13
Copyright © 2009 Pearson Education, Inc. Figure 15.14
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15.5 Organisms Use DNA Repair Systems to Counteract Mutations
Nucleotide Excision Repair and Xeroderma Pigmentosum in Humans
Also—defects in pol (eta)
Copyright © 2009 Pearson Education, Inc. Figure 15.15
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15.5 Organisms Use DNA Repair Systems to Counteract Mutations
Double-Strand Break Repair in Eukaryotes
Copyright © 2009 Pearson Education, Inc. Figure 15.16
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 end-joining, which is error-prone and is prominent during G1.
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15.6 The Ames Test Is Used to Assess the Mutagenicity of Compounds
Copyright © 2009 Pearson Education, Inc. Figure 15.17
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15.7 Geneticists Use Mutations to Identify Genes and Study Gene Function
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15.8 Transposable Elements Move within
the Genome and May Create Mutations
Insertion Sequences
Bacterial Transposons
Copyright © 2009 Pearson Education, Inc. Figure 15.18
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The Ac–Ds System in Maize
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Barbara McClintock
Nobel Prize 1983
Copyright © 2009 Pearson Education, Inc. Figure 15.19
Copyright © 2009 Pearson Education, Inc. Figure 15.19a
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Copyright © 2009 Pearson Education, Inc. Figure 15.19c
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Breakage-fusion-bridge cycle
www.biologie.uni-hamburg.de/b-online/ge21/18.jpg
Breakage-fusion-bridge cycle
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Copia Elements in Drosophila
Copyright © 2009 Pearson Education, Inc. Figure 15.20
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P Element Transposons in Drosophila
Transposable Elements in Humans
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Transposons Create Mutations and Provide Raw Material for Evolution
Copyright © 2009 Pearson Education, Inc. Table 22.1
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Transposons Use Two Different Methods to Move Within Genomes
DNA Transposons and Transposition
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Transposons Use Two Different Methods to Move Within Genomes
Retrotransposons and Transposition
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