1. DNA Mutations and Repair
Chapter 17
Part 1

2. Gene Mutations and Repair
Nature of mutations
Causes of mutations
Study of mutations
DNA repair

3. Nature of Mutations
Chernobyl, April 26th, 1986

4. Mutation: is defined as an inherited change in genetic information by cell division or individual organisms.

5. Mutations can be classified into categories.
Categories of mutations

6. Somatic and germ line

7. Achondroplasia
Autosomal Dominant

8. Gene Mutations can also be classified by type of mutation
1. Base Substitutions
□ 2. Insertions and deletions
3. Frameshift mutations
4. Expanding trinuleotide repeats
Lead to

9. Gene Mutations can also be classified by type of mutation
Base Substitutions
Transitions and Transversions
can be

10. PURINE TO PYRIMIDINE PYRIMIDINE TO PURINE
PURINE TO PURINE

11. Expanding trinucleotide repeats

12. Fragile X Syndrome
Pre-mutation

13. Fragile X syndrome:FMR-1 gene

15. Strand slippage may cause repeats

16. Spontaneous: slippage

17. Phenotypic changes and mutations

18. Reverse mutation
Forward mutation

19. Forward versus Reverse Mutations

20. Terms associated with PHENOTYPIC effects of mutations on protein structure
Can be “neutral”
redundancy

21. Phenotypic effects can also change function
Gain of Gene Function1
Loss of Gene Function2
1 Sullivan, J.P. et al.,
Department of Pathology,
College of Veterinary Medicine, 1998
The University of Georgia, Athens, GA or
Qualtek Molecularlabs Web Site

22. Loss of Function can also occur!
Typically recessive mutations!

23. Suppressor Mutations is a genetic change that hides the effect of another mutation

24. Intragenic Suppressor Mutations

25. Intergenic Mutation

26. Lethal Mutations

27. Do you remember something about each type of mutation?