1. Gene Mutations
Essential Question: How do changes in the DNA nucleotide sequence affect the resulting protein?

2. Any mistake or change in DNA sequence
Mutations
Any mistake or change in DNA sequence
What causes them?
Random or Environment influences – X-rays, UV rays, radioactive materials, chemicals, medications

3. More about mutations Can be beneficial, harmless, or harmful
2 types: Gene & Chromosomal

4. Chromosomal mutation: affects whole or part of a chromosome
Gene mutation:
Changes to the bases in the DNA of ONE gene

5. 1. Gene Mutations Change in one or more nucleotides
Affects the amino acids and protein produced
2 types

6.  Point Mutation Change in a single base pair in DNA Ex:
The dog bit the CAT
The dog bit the CAR

8. Sickle Cell Anemia

9. Some Point Mutations are Harmless
What amino acid is represented by the DNA sequence GGA?
What amino acid is represented by the DNA sequence GGC?
This change in the 3rd base of the codon is a point mutation, yet the amino acid would remain the same. Therefore, the protein would NOT be affected.

10. Some Point Mutations are Harmless
This type of point mutation is called a silent mutation.
Silent Mutations are possible due to the redundancy in the genetic code.

11.  Frameshift Mutation Single base pair is added or deleted from DNA
Ex: Cystic Fibrosis

12. FRAME SHIFT MUTATION Causes a shift in the “reading frame”
thefatcatatetherat
____________________
INSERTION
thefatcataatetherat
DELETION
the fat cat ate the rat
the fat cat aat eth era t
the fat ata tet her at

13. FRAME SHIFTS
Frame shift mutations change every ___________ in the ___________ that follows the shift.
Frame shifts can alter a protein so much it is unable to _____________
Amino acid
protein
function

14. Location of the shift is important!
AT BEGINNING
the fat cat ate the rat
AT END
the fac ata tet her at
the fat cat ate thr at
MUTATIONS AT _____________OF GENE DAMAGE __________ OF THE CODE!
BEGINNING
MORE

15. Nonsense Mutations
A point mutation or a shift in the reading frame can sometimes cause a premature STOP codon
This type of mutation is called a nonsense mutation
If the nonsense mutation occurs early in the mRNA sequence, the protein is greatly shortened and most likely non functional

16. Some mutations are beneficial
Gain-of-function mutations produce a functional protein that results in an entirely new trait
These mutations are usually beneficial and result in an advantage in an organism’s environment
EX: The mutation that resulted in eyesight

17. Practice – Name that Mutation1 2 4 3 6 5