Question

What finding(s) indicate(s) that the highlighted sequence in Toolbox is unlikely to be the correct one that is coded by the DNA sequence from the clone? Check all that apply

Option 1: Low sequence similarity in BLASTX results.
Option 2: Lack of a start codon in the sequence.
Option 3: Presence of a stop codon within the highlighted region.
Option 4: Presence of a polyA tail at the end of the sequence.

Answer 1

Low sequence similarity, absence of a start codon, presence of a premature stop codon, and presence of a polyA tail all indicate that the sequence under investigation may not be the correct one coded by the respective DNA from the clone.

Step-by-step explanation:

When using BLAST to compare a DNA sequence from a clone to known sequences, several findings can indicate that the highlighted sequence is unlikely to be the correct one.

Option 1: Low sequence similarity in BLASTX results suggests that the sequence does not have much in common with known protein-coding sequences.

Option 2: Lack of a start codon in the sequence is a problem because the start codon ATG is necessary for initiating translation.

Option 3: Presence of a stop codon within the highlighted region means translation would be terminated prematurely, which may suggest it is not a coding region.

Lastly, Option 4: Presence of a polyA tail at the end of the sequence is usually found at the end of mRNA transcripts, signaling the end of the coding sequence and thus should not be within the coding region of a cloned DNA sequence.