1. DNA (Gene) Mutations

2. Gene Mutations Change in the nucleotide sequence of a gene
May only involve a single nucleotide
May be due to copying errors, chemicals, viruses, etc.

3. How common are mutations?
Mutations occurs at a frequency of about 1 in every 1 billion base pairs
Everybody has about 6 mutations in each cell in their body!
A fun fact about how common mutations are. Explain that everyone has mutations, although they are not always seen because the mutation may have occurred in a section of DNA that doesn’t make a protein.

4. If I have that many mutations, why don’t I look weird?
Mutations are not always seen. Every part of your DNA doesn’t make a protein or trait.
Explain that everyone has mutations, although they are not always seen because the mutation may have occurred in a section of DNA that doesn’t make a protein or the mutation may cause a cell to die (while not affecting the function of the organ).

5. Types of Gene Mutations
Include:
Point Mutations
Substitutions
Insertions
Deletions
Frameshift

6. Point Mutation Change of a single nucleotide
Includes the deletion, insertion, or substitution of ONE nucleotide in a gene

7. DNA (Gene) Mutation What has happened to the normal DNA?
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TGC - TTC
Ask students if they can figure out what is happening in this mutation.
Answer is on the next slide.
What has happened to the normal DNA?

8. DNA (Gene) Mutation *Adenine was accidentally replaced with thymine
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TGC - TTC
See if students can figure out what the name of this mutation would be; answer is on the next slide.
*Adenine was accidentally replaced with thymine
*What is this mutation called?

9. Substitution What will happen to the amino acids?
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TGC - TTC
Explain and emphasize how this type of mutation will only affect one amino acid
What will happen to the amino acids?

10. Point Mutation
Sickle Cell disease is the result of one nucleotide substitution
Occurs in the hemoglobin gene

11. DNA (Gene) Mutation What has happened to the normal DNA?
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TAG – CAT - C
Ask students if they can figure out what is happening in this mutation.
Answer is on the next slide.
What has happened to the normal DNA?

12. DNA (Gene) Mutations
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TAG – CAT - C
*Adenine was inserted,causing the remaining DNA to shift to the right
*What is this mutation called?
See if students can figure out what the name of this mutation would be; answer is on the next slide.

13. Insertion What will happen to the amino acids?
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TAG – CAT - C
Also, explain and emphasize how this type of mutation will affect all the amino acids after the mutation
What will happen to the amino acids?

14. DNA (Gene) Mutation What has happened to the normal DNA?
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TCA- TC
Ask students if they can figure out what is happening in this mutation.
Answer is on the next slide.
What has happened to the normal DNA?

15. DNA (Gene) Mutation
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TCA- TC
See if students can figure out what the name of this mutation would be; answer is on the next slide.
*Guanine was removed, causing the remaining DNA to shift to the left
*What is this mutation called?

16. Deletion What will happen to the amino acids?
Normal DNA: CGA – TGC – ATC
Mutated DNA: CGA – TCA- TC
Explain and emphasize how this type of mutation will affect all the amino acids after the mutation
What will happen to the amino acids?

17. Frameshift Mutation Inserting or deleting one or more nucleotides
Changes the “reading frame” like changing a sentence
Proteins built incorrectly

18. Frameshift Mutation Original: The fat cat ate the wee rat.
Frame Shift (“a” added):
The fat aca tat eth ewe era t.

19. Amino Acid Sequence Changed

20. Gene Mutation Animation

21. • What causes mutations?
has a mutation?
• What happens to a person who
Explain that many mutations occur naturally (when your DNA replicates before cell division). Many mutations are caused by mutagens (UV light, exposure to chemicals, radiation, etc.)
What happens? Most of the time the mutation is harmless because there are sections of DNA that do not code for protein (junk DNA) but sometimes the mutations can cause disorders such as Huntington’s disease and sickle cell anemia.

22. have the least effect on an
• Which mutation would
organism?
have the least effect on an
• When would a mutation
an organism?
have the most effect on
Least Effect? A mutation on an unexpressed recessive trait or substitution because it only affects ONE amino acid; insertion and deletion affect ALL the amino acids after the mutation.
Most Effect? Mutations in egg and sperm cells can cause problems in the baby whereas mutations in body cells can only cause problems for that person (not his/her offspring).