A mutation is a change in DNA sequence that can be caused by copying errors during DNA replication or exposure to mutagens like UV light or chemicals. There are several types of mutations, including point mutations which change a single DNA base pair, frameshift mutations which insert or delete base pairs changing all subsequent amino acids, and chromosomal mutations which involve gains or losses of entire chromosomes during meiosis. These mutations can have varying effects from no effect to large negative effects depending on the type of mutation and which gene is affected.

1. Notes: Mutations (page 10)
• Mutation = A change in DNA sequence

2. Notes: Mutations (page 10)
• Mutation = A change in DNA sequence
• Caused by copying errors during DNA
replication or by mutagens (UV light, certain
chemicals)

3. Notes: Mutations (page 10)
• Mutation = A change in DNA sequence
• Caused by copying errors during DNA
replication or by mutagens (UV light, certain
chemicals)
• Usually harmful, but sometimes beneficial

4. Gene Mutations
1. Point mutation = a change in a single base
pair of DNA

5. Gene Mutations
1. Point mutation = a change in a single base
pair of DNA
• Example: ATTCCG becomes ATACCG

6. Gene Mutations
1. Point mutation = a change in a single base
pair of DNA
• Example: ATTCCG becomes ATACCG
• Can have no effect or a large effect (sickle cell
anemia)

7. 2. Frameshift Mutation = Insertion or deletion of
a DNA base

8. 2. Frameshift Mutation = Insertion or deletion of
a DNA base
Example: ATTCCG becomes ATCCG

9. 2. Frameshift Mutation = Insertion or deletion of
a DNA base
Example: ATTCCG becomes ATCCG
Changes every amino acid in the protein after
the insertion or deletion

10. 2. Frameshift Mutation = Insertion or deletion of
a DNA base
Example: ATTCCG becomes ATCCG
Changes every amino acid in the protein after
the insertion or deletion
Usually have a large negative effect

11. Chromosomal mutations
• Usually we have 2 copies of each chromosome
(1 from mom, 1 from dad)

12. Chromosomal mutations
• Usually we have 2 copies of each chromosome
(1 from mom, 1 from dad)
• Errors in meiosis (the process of making eggs
and sperm) can cause people to end up with 1
copy (monosomy) or 3 copies (trisomy) of a
chromosome

13. Chromosomal mutations
• Usually we have 2 copies of each chromosome
(1 from mom, 1 from dad)
• Errors in meiosis (the process of making eggs
and sperm) can cause people to end up with 1
copy (monosomy) or 3 copies (trisomy) of a
chromosome
• Example: 3 copies of Chromosome 21 =
Downs syndrome

14. • Polyploidy = extra copies of all chromosomes

15. • Polyploidy = extra copies of all chromosomes
• Common in plants

16. • Polyploidy = extra copies of all chromosomes
• Common in plants
• Example: Triploid plants have 3 copies of each
chromosome, Tetraploid have 4 copies, etc.