Gene Mutation

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Gene Mutation
Mutation
Chromosome mutations/aberrations
Classification of Mutations
1. Spontaneous vs. Induced Spontaneous mutation
Induced mutation
2. Gametic vs. Somatic Somatic mutation
Gametic mutation
3. Other categories
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Gene Mutation
How are mutations detected in humans?
Pedigree analysis
Cells cultured in vitro Analysis of enzyme
activity, sequencing of proteins and DNA
The molecular basis of mutation (Point mutations)
1. Base substitution transition transversion
2. Frame shift
3. Tautomeric shift
4. Base analogs
5. Chemical mutagens
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Gene Mutation
3.Ionizing radiation
The molecular basis of mutation (Structural
damage)
1. Missing bases
N-glycosidic bond very weak and easily broken
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Gene Mutation
Mutations in humans
ABO Blood Types
A
A
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Gene Mutation
DNA Repair
1. Photoreactivation
PRE photoreactivation enzyme
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Gene Mutation
3. Excision repair
DNA Repair
2. 3 to 5 exonuclease activity of DNA
polymerases
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Gene Mutation
3. Excision repair
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Gene Mutation
4. Post-replication repair (recombination repair)
recombined
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Gene Mutation
5. Inducible repair or SOS (prokaryotes)
Its better to be a mutant than be dead!