1. Mutations 1

2. Mutations
Change in any part of DNA/Changes in the nucleotide sequence of DNA
May occur in somatic cells (not passed to offspring)
May occur in gametes (eggs & sperm) and be passed to offspring 2

3. Mutations
Mutations can occur in any cell. They only affect future generations if they occur in the cells that produce the gametes: these are “germinal” or “germ line” mutations.
Mutations in other cells are rarely noticed, except in the case of cancer, where the mutated cell proliferates uncontrollably. Mutations in cells other than germ line cells are “somatic” mutations.

4. Mutations
A human body contains cells approximately. The average mutation rate for any given nucleotide is about 1 in That is, on the average 1 cell in 109 has that particular nucleotide altered. This means that virtually every possible base change mutation occurs repeatedly in our body cells.

5. What Causes Mutations?
There are two ways in which DNA can become mutated:
Mutations can be inherited.
Parent to child
Mutations can be acquired.
Environmental damage

6. Significance of Mutations
Most are neutral
Eye color
Birth marks
Some are harmful
Sickle Cell Anemia
Down Syndrome
Some are beneficial
Sickle Cell Anemia to Malaria
Immunity to HIV

7. Are Mutations Helpful or Harmful?
Mutations happen regularly
Almost all mutations are neutral
Chemicals & UV radiation cause mutations
Many mutations are repaired by enzymes 7

8. Are Mutations Helpful or Harmful?
Some type of skin cancers and leukemia result from somatic mutations
Some mutations may improve an organism’s survival (beneficial) 8

9. Types of Mutations
Chromosome Mutations
Gene mutation

10. Chromosome Mutations May Involve:
Changing the structure of a chromosome
The loss or gain of part of a chromosome 10

11. Chromosome Mutations Five types exist: Deletion Inversion
Translocation
Non disjunction
Duplication 11

12. Deletion
Due to breakage
A piece of a chromosome is lost 12

13. Inversion Chromosome segment breaks off Segment flips around backwards
Segment reattaches 13

14. Duplication
Occurs when a gene sequence is repeated 14

15. Translocation Involves two chromosomes that aren’t homologous
Part of one chromosome is transferred to another chromosomes 15

16. Translocation 16

17. Non disjunction Failure of chromosomes to separate during meiosis
Causes gamete to have too many or too few chromosomes 17

18. 18

19. Chromosome Mutations Down Syndrome:
Chromosome 21 does not separate correctly.
They have 47 chromosomes in stead of 46.
Children with Down Syndrome develop slower, may have heart and stomach illnesses and vary greatly in their degree of intelligence.

20. Chromosome Mutations Cri-du-chat:
Deletion of material on 5th chromosome
Characterized by the cat-like cry made by cri-du-chat babies
Varied levels of metal handicaps

21. Chromosome Mutation Animation21

22. 22

23. 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. 23

24. Types of Gene Mutations
Include:
Point Mutations
Substitutions
Insertions
Deletions
Frame shift 24

25. Point Mutation Change of a single nucleotide
Includes the deletion, insertion, or substitution of ONE nucleotide in a gene 25

26. Point Mutation
Sickle Cell disease is the result of one nucleotide substitution
Occurs in the hemoglobin gene 26

27. Frame shift Mutation Inserting or deleting one or more nucleotides
Changes the “reading frame” like changing a sentence
Proteins built incorrectly 27

28. Frame shift Mutation Original: The fat cat ate the wee rat.
Frame Shift (“a” added):
The fat caate the wee rat. 28

29. Amino Acid Sequence Changed29

30. Gene Mutation Animation30