1. 6.2 Mutations Pages 234-239

2. Mutations can be caused by: - environmental agents - errors during cell division

3. Radiation Exposure to radioactive materials can cause genetic mutations.

4. Chemicals Examples: Nitrosonguanidine (NTG), Hydroxylamine, Bromodeoxyuridine (BrdU), and Ethidium bromide

5. Effects Positive, negative or neutral effect on phenotype or cell death

6. Point Mutations A failure of the genetic machinery to copy the DNA perfectly.

7. Base-pair substitution The wrong nitrogenous base pair is included.

8. Insertion Extra nitrogenous bases are included during the copying of the DNA.

9. Deletions One or more base pairs are left out during the copying of DNA

10. Chromosome mutations Involve the entire chromosome or major chunks Non-disjunction (sister chromatids fail to separate during meiosis) Down syndrome Turner syndrome Patau syndrome

11. Chromosome mutations Large scale deletions, insertions, duplications or inversions (flipping) of entire portions of a chromosome

12. Inheriting mutations The genetic machinery is designed to find and fix copying errors. (less successful with age)

13. Inheriting mutations Most of the DNA does not code for genes (so errors here are meaningless)

14. Inheriting mutations Mutations in autosomes are not passed on to the next generation

15. Inheriting mutations Mutations in sex cells can be passed on to the next generation

16. Dominant vs. Recessive Mutations can be dominant and appear in the first generation. Ex. Huntington’s disease Mutations can be recessive and appear only rarely when two individuals with the same mutation produce offspring. Ex. Cystic Fibrosis

17. Sickle cell anemia Misshapen red blood cells can cause pain and an increased risk of infection

18. Sickle cell anemia Malaria parasite enters red blood cell causing it to become sickle-shaped and leading to its destruction and removal.

19. Lactose Tolerance Most babies tolerate lactose producing the enzyme needed to digest their mother’s milk 75% of adults do not tolerate lactose 25% of adults have a mutation in their genes that allows them to digest lactose.

20. Spontaneous mutations Happen by accident

21. Induced mutations Result due to exposure to a physical or chemical agent

22. Antibiotic Resistance Usually antibiotics kill bacteria by weakening their cell wall. Mutations in genes that code for the cell wall allow the bacteria to be resistant to antibiotics.

23. Jumping Genes Transposons are segments of the DNA that can move from place to place. Transposition is the act of moving a segment of DNA from one place to another. Example: Indian corn

24. hemophilia A transposon can insert itself into a gene for normal blood factor VIII, causing hemophilia in boys (X-linked gene).

25. Microarray Technology Microarray -small membrane or glass slide -contains samples of hundreds or even thousands of DNA fragments -arranged in a regular pattern. -Each fragment corresponds to a gene

26. Microarray