Question

there are several types of mutation: >deletion (a base is lost/deleted) >insertion (an extra base is added/inserted) — deletion & insertion may cause whats 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, its called a missense mutation — if a substitution does not change the amino acid, its called a silent mutation — if a substitution changes the amino acid to a \stop,\ its 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: tacaccttggcgacgact... mrna sequence: amino acid sequence: mutated dna sequence #1 tacatcttggcgacgact... whats the mrna sequence? (circle the change) amino acid sequence? will there likely be effects? what type of mutation is this? mutated dna sequence #2 tacgaccttggcgacgact... whats the mrna sequence? (circle the change) amino acid sequence? will there likely be effects? what type of mutation is this? mutated dna sequence #3 tacaccttagcgacgact... whats the mrna sequence? (circle the change) amino acid sequence? will there likely be effects? what type of mutation is this? mutated dna sequence #4 tacaccttggcgactact... whats the mrna sequence? (circle the change) amino acid sequence? will there likely be effects? what type of mutation is this?

Explanation:

Step1: Transcribe original DNA to mRNA

Use base - pairing rules (A - U, T - A, G - C, C - G). Original DNA: TACACCTTGGCGACGACT. mRNA: AUGUGGAACCGCUGCUGA.

Step2: Translate mRNA to amino - acid sequence

Use the genetic code. mRNA: AUGUGGAACCGCUGCUGA. Amino - acid sequence: Methionine - Tryptophan - Asparagine - Proline - Cysteine - Stop.

Mutated DNA Sequence #1: TACATCTTGGCGACGACT

Step1: Transcribe mutated DNA to mRNA

Base - pairing gives AUGUAGAACCGCUGCUGA. The changed base in mRNA is UAG (circled).

Step2: Translate mRNA to amino - acid sequence

AUG (Methionine), UAG (Stop), AAC (Asparagine), CGC (Arginine), UGC (Cysteine), UGA (Stop).

Step3: Determine effects and mutation type

There will likely be effects as the protein will be prematurely terminated. This is a substitution (T to A in DNA) and a nonsense mutation.

Mutated DNA Sequence #2: TACGACCTTGGCGACGACT

Step1: Transcribe mutated DNA to mRNA

Base - pairing gives AUGCUGGAACCGCUGCUGA. The changed base in mRNA is CUG (circled).

Step2: Translate mRNA to amino - acid sequence

AUG (Methionine), CUG (Leucine), GGA (Glycine), CCG (Proline), CUG (Leucine), UGA (Stop).

Step3: Determine effects and mutation type

There will likely be effects as the amino - acid sequence is changed. This is a substitution (A to G in DNA) and a missense mutation.

Mutated DNA Sequence #3: TACACCTTAGCGACGACT

Step1: Transcribe mutated DNA to mRNA

Base - pairing gives AUGUGGAAUCGCUGCUGA. The changed base in mRNA is AAU (circled).

Step2: Translate mRNA to amino - acid sequence

AUG (Methionine), UGG (Tryptophan), AAU (Asparagine), CGC (Arginine), UGC (Cysteine), UGA (Stop).

Step3: Determine effects and mutation type

There will likely be no effects as the amino - acid sequence is not changed at the position of the mutation. This is a substitution (G to A in DNA) and a silent mutation.

Mutated DNA Sequence #4: TACACCTTGGCGACTACT

Step1: Transcribe mutated DNA to mRNA

Base - pairing gives AUGUGGAACCGCUGAUGA. The changed bases in mRNA are UGA and AUG (circled).

Step2: Translate mRNA to amino - acid sequence

AUG (Methionine), UGG (Tryptophan), AAC (Asparagine), CGC (Arginine), UGA (Stop), AUG (Methionine), UGA (Stop).

Step3: Determine effects and mutation type

There will likely be effects as the reading frame is shifted. This is an insertion (an extra base in DNA) and a frameshift mutation.

Answer:

Original DNA Sequence: TACACCTTGGCGACGACT
mRNA Sequence: AUGUGGAACCGCUGCUGA
Amino Acid Sequence: Methionine - Tryptophan - Asparagine - Proline - Cysteine - Stop

Mutated DNA Sequence #1: TACATCTTGGCGACGACT
mRNA sequence: AUGUAGAACCGCUGCUGA (UAG circled)
amino acid sequence: Methionine - Stop - Asparagine - Arginine - Cysteine - Stop
Will there likely be effects? Yes
What type of mutation is this? Substitution, Nonsense

Mutated DNA Sequence #2: TACGACCTTGGCGACGACT
mRNA sequence: AUGCUGGAACCGCUGCUGA (CUG circled)
amino acid sequence: Methionine - Leucine - Glycine - Proline - Leucine - Stop
Will there likely be effects? Yes
What type of mutation is this? Substitution, Missense

Mutated DNA Sequence #3: TACACCTTAGCGACGACT
mRNA sequence: AUGUGGAAUCGCUGCUGA (AAU circled)
amino acid sequence: Methionine - Tryptophan - Asparagine - Arginine - Cysteine - Stop
Will there likely be effects? No
What type of mutation is this? Substitution, Silent

Mutated DNA Sequence #4: TACACCTTGGCGACTACT
mRNA sequence: AUGUGGAACCGCUGAUGA (UGA and AUG circled)
amino acid sequence: Methionine - Tryptophan - Asparagine - Arginine - Stop - Methionine - Stop
Will there likely be effects? Yes
What type of mutation is this? Insertion, Frameshift