MUTATED DNA Sequence #3 ➔ T A C A C C T T A G C G A C G A C T

Question

What is the mRNA sequence? (Circle the change)
amino acid sequence?
Will there likely be effects? What type of mutation is this?

Answer 1

To convert a mutated DNA sequence into an mRNA sequence, you follow the base pairing rules, with the exception that in RNA, uracil (U) replaces thymine (T). The DNA template strand will be used to create an mRNA strand, which is synthesized in the 5’ to 3’ direction.

Given Mutated DNA Sequence: 5’ T A C A C C T T A G C G A C G A C T 3’

mRNA Sequence: To get the corresponding mRNA, we will transcribe each DNA base into its RNA complement:

• T → A
• A → U
• C → G
• G → C

So the mRNA sequence is:

5’ A U G U G G A A U C G C U G C U G A 3’

Circled Change: The original DNA sequence would contain some kind of base that was altered to create the current sequence. However, in the information provided to me, the original sequence is not included, so I cannot identify the specific change or mutation without this context.

Amino Acid Sequence: Next, we can translate the mRNA sequence into an amino acid sequence using the codon table:

1. AUG → Methionine (Met, M)
2. UGG → Tryptophan (Trp, W)
3. AAU → Asparagine (Asn, N)
4. CGC → Arginine (Arg, R)
5. UGC → Cysteine (Cys, C)
6. UGA → Stop (this signals the termination of translation)

The amino acid sequence derived from the mRNA would be:

Amino Acid Sequence: Met-Trp-Asn-Arg-Cys-Stop

Regarding potential effects and the type of mutation:

Likely Effects:

• The mutation can have a range of effects depending on where it occurred (in coding regions, regulatory elements, etc.).
• If this mutation resulted in a change to the amino acid sequence (or added premature stop codons), it could lead to non-functional or less effective proteins, potentially resulting in phenotypic changes.

Type of Mutation:

• If you identify the specific changed nucleotide(s) from the original sequence, you can categorize the mutation. Broadly, it could be a:
  • Missense mutation (if it changes one amino acid),
  • Nonsense mutation (if it introduces a stop codon),
  • Silent mutation (if it does not change the amino acid but changes the codon),
  • Frameshift mutation (if nucleotides are added or deleted causing a shift in the reading frame).

Since the information on the original sequence is not provided, a definitive conclusion on the type of mutation cannot be made. If you have access to that original DNA sequence, I could help identify the specific change and category of mutation.