1. Mutations

2. Gene Mutation Gene mutation is a change in base code sequence
Errors in replication
Rare
DNA polymerase & repair enzymes “proof reads” new strands
Mutagens
Environmental influences
Radiation, UV light, chemicals
Rate is low
Transposons
“jumping genes”
Can move to new locations and disrupt sequences

3. Point Mutations Point Mutations Change in a single nitrogen base
Examples:
Insertion
Deletion
Substitution

4. Frameshift mutations
Frameshift mutation is when an entire sequence of amino acids is interrupted/changed
Caused by
insertions
Transposons
deletions

5. Mutations
Missense mutations
Change in only a few amino acids  protein can function, but causes problems (sickle cell anemia)
EX: THE CAT ATE THE HAT
THE MAT ATE THE HAT

6. Mutation
Silent mutations
No change in Amino Acid (redundancy)

7. Frameshift Mutation
Change “coding frame” (how the codon is read)

8. Frameshift mutation
Nonsense mutations
Changes whole amino acid sequence  protein can’t function
Changes the amino acid codon to a stop
Ex: THE CAT ATE THE HAT
THE CAT

9. Transposons Discovered by Barbara McClintock
“Jumping Genes”  genes that can “move” within or between chromosomes
May increase or decrease gene expression
May destroy gene expression

10. Learning Check! What can cause a mutation?
What type of mutation does not lead to a different amino acid/protein?
What type of mutation causes the protein to stop early?
What type of mutation changes one or two amino acids, but the protein still functions more or less?