Question

NAME __________________________________ Mutations Worksheet
Deletion, Insertion & Substitution
There are several types of mutation:
➢ DELETION (a base is lost/deleted)
➢ INSERTION (an extra base is added/inserted)
--- Deletion & insertion may cause what’s called a FRAMESHIFT mutation, meaning the reading “frame"
changes, thus changing the amino acid sequence from this point forward
➢ SUBSTITUTION (one base is substituted for another)
--- If a substitution changes the amino acid, it’s called a MISSENSE mutation
--- If a substitution does not change the amino acid, it’s called a SILENT mutation
--- If a substitution changes the amino acid to a “stop,” it’s called a NONSENSE mutation
Complete the boxes below. Classify each as Deletion, Insertion or Substitution AND as either
frameshift, missense, silent or nonsense (Hint: Deletion & Insertion will always be frameshift).
ORIGINAL DNA Sequence ➔ T A C A C C T T G G C G A C G A C T
What is the mRNA sequence?
amino acid sequence?
MUTATED DNA Sequence #1 ➔ T A C A T C T T G G C G A C G A C T
What is the mRNA sequence? (Circle the change)
amino acid sequence?
Will there likely be effects? What type of mutation is this? ______________________________
MUTATED DNA Sequence #2 ➔ T A C G A C C T T G G C G A C G A C T
What is the mRNA sequence? (Circle the change)
amino acid sequence?
Will there likely be effects? What type of mutation is this? ______________________________
MUTATED DNA Sequence #3 ➔ T A C A C C T T A G C G A C G A C T
What is the mRNA sequence? (Circle the change)
amino acid sequence?
Will there likely be effects? What type of mutation is this? ______________________________
MUTATED DNA Sequence #4 ➔ T A C A C C T T G G C G A C T A C T
What is the mRNA sequence? (Circle the change)
amino acid sequence?
Will there likely be effects? What type of mutation is this? ____________________________

Answer 1

Let's break down the requested tasks based on the original DNA sequence and the mutated sequences provided.

### Original DNA Sequence
- Original sequence: **T A C A C C T T G G C G A C G A C T**
- mRNA sequence: (transcribing the DNA to RNA, replacing Thymine (T) with Uracil (U))
**A U G U G G A A C C G C U G C U G A**
- Amino acid sequence: (using the codon chart)
AUG - Met (Methionine)
UGG - Trp (Tryptophan)
AAC - Asn (Asparagine)
CGC - Arg (Arginine)
UGC - Cys (Cysteine)
UGA - Stop
**Amino acid sequence: Met-Trp-Asn-Arg-Cys**

---

### Mutated DNA Sequence #1
- Mutated sequence: **T A C A T C T T G G C G A C G A C T**
- mRNA sequence:
**A U G U A G A A C C G C U G C U G A** (Circle change: T(A) → T(A) *T* → A(T)*)
- Amino acid sequence:
AUG - Met (Methionine)
UAG - Stop
**Amino acid sequence: Met-Stop**
- Likely effects: Yes, likely to be significant due to an early stop codon.
- Type of mutation: **Substitution, Nonsense mutation**

---

### Mutated DNA Sequence #2
- Mutated sequence: **T A C G A C C T T G G C G A C G A C T**
- mRNA sequence:
**A U G C U G G A A C C G C U G C U G A** (Circle change: T(A) → G(C))
- Amino acid sequence:
AUG - Met (Methionine)
CUG - Leu (Leucine)
GAA - Glu (Glutamic acid)
CGC - Arg (Arginine)
UGC - Cys (Cysteine)
UGA - Stop
**Amino acid sequence: Met-Leu-Glu-Arg-Cys**
- Likely effects: Yes, it likely changes the function of the protein.
- Type of mutation: **Substitution, Missense mutation**

---

### Mutated DNA Sequence #3
- Mutated sequence: **T A C A C C T T A G C G A C G A C T**
- mRNA sequence:
**A U G U G G A A U C G C U G C U G A** (Circle change: T(T) → A(A))
- Amino acid sequence:
AUG - Met (Methionine)
UGG - Trp (Tryptophan)
AAU - Asn (Asparagine)
CGC - Arg (Arginine)
UGC - Cys (Cysteine)
UGA - Stop
**Amino acid sequence: Met-Trp-Asn-Arg-Cys**
- Likely effects: There could be minimal effects as it’s likely a silent mutation.
- Type of mutation: **Substitution, Silent mutation**

---

### Mutated DNA Sequence #4
- Mutated sequence: **T A C A C C T T G G C G A C T A C T**
- mRNA sequence:
**A U G U G G A A C C G C U G A U G A** (Circle change: C(G) → T(A))
- Amino acid sequence:
AUG - Met (Methionine)
UGG - Trp (Tryptophan)
AAC - Asn (Asparagine)
CGU - Arg (Arginine)
AUC - Ile (Isoleucine)
Stop - Codon
**Amino acid sequence: Met-Trp-Asn-Arg-Ile**
- Likely effects: Yes, it causes a shift in the amino acid sequenсe.
- Type of mutation: **Insertion, Frameshift mutation**

---

To summarize the effects and types of mutations for each of the sequences:

1. **Mutation #1**: Substitution, **Nonsense Mutation**
2. **Mutation #2**: Substitution, **Missense Mutation**
3. **Mutation #3**: Substitution, **Silent Mutation**
4. **Mutation #4**: Insertion, **Frameshift Mutation**