1. Mutations
12-4

2. Mutations
Mutation: a change in DNA sequence that affects the genetic information.
Gene mutations: changes in a single gene-causes point or frame shift mutations
Chromosomal mutations: changes in part or a whole chromosome

3. Gene Mutations Point mutations: affect only one nucleotide CATCATCAT
1. Substitutions
CATCATCAT
CATCTTCAT
Ex.-Sickle cell anemia

5. Gene Mutations
Frame shift mutations: change in one nucleotide affects all following nucleotides
2. Insertion
CATTAGCAT
CATTAGGCAT
3. Deletion Ex.- CF
CATTGCAT

10. Chromosomal Mutations
Change in the number or structure of chromosomes.
1. Deletion: loss of all or part of a chromosome
Ex.-Cri-du-chat & Turner’s syndrome
2. Duplication: segment of chromosome is repeated
3. Inversion: segments are reversed

11. Chromosomal Mutations
4. Translocation: part breaks off and attaches to a non-homologous chromosome
5. Insertion: gain part of or a whole extra chromosome. Ex.-Down syndrome
Look at examples on p. 346!

16. Cause and Effect Some inversions cause miscarriages.
Several types of cancer are caused by translocations (leukemia).
Mutagens are substances that cause mutations. Ex- X rays, certain chemicals, radiation