Mutated DNA Sequence #2 (Circle the change) What’s the mRNA sequence? amino acid sequence? Will there likely be effects? What type of mutation is this? TACACCTTGGCGACTACT
The Correct Answer and Explanation is:
Answer:
- mRNA Sequence: AUGUGGAACCGCUGAUGA
- Amino Acid Sequence: Met-Trp-Asn-Arg (Translation stops prematurely)
- Will there likely be effects? Yes, the premature stop codon likely leads to a truncated and nonfunctional protein.
- Type of Mutation: Nonsense mutation
Explanation:
DNA contains the instructions for synthesizing proteins, and mutations can alter these instructions. The given DNA sequence is transcribed into messenger RNA (mRNA) by replacing thymine (T) with uracil (U), producing the mRNA sequence AUGUGGAACCGCUGAUGA. Each three-letter segment of the mRNA, known as a codon, is then translated into amino acids based on the genetic code.
This specific mRNA sequence translates as follows:
- AUG: Methionine (Start codon)
- UGG: Tryptophan
- AAC: Asparagine
- CGC: Arginine
- UGA: Stop codon
The presence of UGA as a stop codon halts translation prematurely, leading to an incomplete protein. Proteins require a full sequence of amino acids to function correctly, and a truncated structure often results in a loss of functionality. This premature termination is known as a nonsense mutation, as it converts a codon that should code for an amino acid into a stop codon.
Nonsense mutations can have severe consequences depending on the role of the affected protein. If the mutation occurs in a critical gene, essential cellular processes may be disrupted, leading to diseases or developmental issues. The severity of the effect depends on whether the mutation eliminates a crucial part of the protein’s active site or structural integrity.
This mutation likely prevents the protein from carrying out its intended function, possibly resulting in significant biological consequences. Identifying and understanding such mutations is essential in genetic research and medical diagnostics.
