1. DNA Mutations and Repair Chapter 18 Part 1

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

3. Chernobyl, April 26 th, 1986 Source of Mutations Nuclear accidents

4. Source of Mutations Japan’s Tsunami disabled reactors at the Fukushima Plant March 11, 2001

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

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

7. Somatic and germ line

8. Achondroplasia Autosomal Dominant

9. 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

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

11. PURINE TO PURINE PURINE TO PYRIMIDINE PYRIMIDINE TO PURINE

12. Expanding trinucleotide repeats

13. Fragile X Syndrome Pre-mutation

14. Fragile X syndrome:FMR-1 gene

15. Update on diagnosis of fragile X Syndrome: Fragile X syndrome was originally diagnosed by culturing cells in a folate deficient medium and then assessing the cultures for X-chromosome breakage by cytogenetic analysis of the long arm of the X- chromosome. This technique proved unreliable for both diagnosis and carrier testing. cytogenetic The fragile X abnormality is now directly determined by analysis of the number of CGG repeats and their methylation status using: restriction endonucleaserestriction endonuclease digestion and Southern blot analysis.Southern blot

17. Strand slippage may cause repeats

18. Phenotypic changes and mutations

19. Spontaneous: slippage

20. Reverse mutation Forward mutation

21. Forward versus Reverse Mutations

22. Terms associated with PHENOTYPIC effects of mutations on protein structure

23. Phenotypic effects can also change function 1 Sullivan, J.P. et al., Department of Pathology, College of Veterinary Medicine, 1998 The University of Georgia, Athens, GA Gain of Gene Function 1 Loss of Gene Function 2 Qualtek Molecularlabs Web Site or

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

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

26. Intragenic Suppressor Mutations

27. Intergenic Mutation

28. Lethal Mutations

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