1. Mutations

2. What Are Mutations?
Changes in the structure of the genetic material of an organism.
May occur in gametes during meiosis (eggs & sperm) and be passed to offspring

3. What are mutations? Mutations happen regularly
Chemicals & UV radiation cause mutations
Many mutations are repaired by enzymes

4. Other mutagenic factors that can alter DNA
Many types of rays can cause mutations
Xrays, ultraviolet rays, microwaves, etc.
Chemicals can also cause mutations
Toxins, hazardous chemicals, carcinogens
Additional mutagenic factor:
The sun!

5. Are Mutations Helpful or Harmful?
Some type of skin cancers and leukemia result from somatic mutations
Almost all mutations are neutral
Some mutations may improve an organism’s survival (beneficial)

6. Types of Mutations

7. Gene Mutations Change in the nucleotide sequence of a gene
May only involve a single nucleotide
May be due to copying errors, chemicals, viruses, etc.

8. Types of Gene Mutations
Include:
Point Mutations
Substitutions
Frameshift
Insertions
Deletions

9. Point Mutation Change of a single nucleotide
Includes the deletion, insertion, or substitution of ONE nucleotide in a gene

10. Point Mutation
Sickle Cell disease is the result of one nucleotide substitution
Occurs in the hemoglobin gene

11. SUBSTITUTION
type of point mutation in which a single nucleotide is substituted with (or exchanged for) a different nucleotide that may result in an altered sequence of amino acid during translation.

13. INSERTION
type of mutation resulting from the addition of extra nucleotides in a DNA sequence or chromosome.

15. DELETION
In genetics, a deletion (also called gene deletion, deficiency, or deletion mutation) is a mutation (a genetic aberration) in which a part of a chromosome or a sequence of DNA is missing

17. Frameshift Mutation Inserting or deleting one or more nucleotides
Changes the “reading frame” like changing a sentence
Proteins built incorrectly

18. Frameshift Mutation Original: The fat cat ate the wee rat
Frame Shift (“a” added):
The fat caa tat eth ewe era t

19. Amino Acid Sequence Changed

20. Gene Mutation Animation

22. Chromosome Mutations May Involve:
Changing the structure of a chromosome
The loss or gain of part of a chromosome

23. Chromosome Mutations Five types exist: Deletion Inversion
Translocation
Nondisjunction
Duplication

24. Deletion
Due to breakage
A piece of a chromosome is lost

25. Duplication
Occurs when a gene sequence is repeated

26. Translocation Involves two chromosomes that aren’t homologous
Part of one chromosome is transferred to another chromosomes

27. Inversion Chromosome segment breaks off Segment flips around backwards
Segment reattaches

28. Translocation

29. Nondisjunction Failure of chromosomes to separate during meiosis
Causes gamete to have too many or too few chromosomes

31. Chromosome Mutation Animation