1. Mutation and Genetic Change
Chapter 14.1

2. Mutations= A change in the structure or amount of genetic material of an organism.

3. I. Causes of Mutations a. Accidental – caused during cell division.
b. Mutagens- caused by environmental factors such as radiation or chemicals.

4. II. Types of Mutations
Gene mutations- Changes within the DNA sequence. (Smaller scale)
i. Point mutation- Change in one single nucleotide (letter).
Original- THE CAT ATE RAT
Mutation- THE TAT ATE RAT

5. II Types of Mutations:
ii. Insertion- One or more nucleotides are added into the sequence.
Original- THE CAT ATE RAT
Mutation- THE CAT AAT ERA T…
iii. Deletion- One or more nucleotides is removed from the sequence.
Mutation- T HC ATA TER AT…

6. II Types of Mutations
v. Missense mutation- A point mutation that does throw off the amino acid sequence.
vi. Frameshift mutation- A mutation that shifts the entire sequence. All insertions and deletions are considered frameshifts.
vii. Nonsense mutation- When the mutation accidentally causes the code for a “stop” amino acid. This causes the protein chain to be cut short.

7. II. Types of Mutations

8. II. Types of Mutations
b. Chromosomal mutations- Mutation in the number of or parts of an entire chromosome.
i. Deletion- When part of a chromosome or gene is removed. Usually harmful.

9. II. Types of Mutations
ii. Duplication- When a part of a chromosome or gene occurs twice on the same chromosome.

10. II. Types of Mutations
iii. Inversion- When two genes on the same chromosome are in reverse order.

11. II. Types of Mutations
iv. Translocation- When a piece of chromosome or a gene ends up on a completely different chromosome

12. II. Types of Mutations
v. Nondisjunction- When the chromosomes do not “sort” correctly during meiosis. Usually end up with an extra chromosome.

13. Mutations c. Effects of Mutations
i.Heritability- Mutations are only able to be inherited by offspring if they affect an individual’s sex cells (gametes).
ii. Cancer/tumors- Some mutations cause somatic cells to lose control of their cell division.

14. Mutations
iii. New alleles- New variations of traits may occur (i.e. new coat colors, new body shapes, etc.).
iv. Genetic disorders- May cause physical or mental disabilities.

15. 14.2 Regulating Gene Expression

16. Gene regulation in prokaryotes