A frameshift mutation through deletion occurs when one or more nucleotides are removed from the DNA sequence, shifting the reading frame of the codons. In this case, we need to identify the option that represents a deletion that alters the codon structure of the original sequence "AGC TTA TCG".
Looking at the responses, let's analyze them:
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AGC TTA TAG - This sequence has changed "TCG" to "TAG". No bases were deleted; this is a substitution, not a deletion.
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AGC TTA TAG (this is a repetition of the previous option) - Same reasoning applies here.
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AGC TTT CG - This sequence changes "TTA" to "TTT" and deletes "T" at the end. This does not create a frameshift as it did not delete a complete codon.
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AGC TTT CG (repetition) - Same as above.
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TTA TCG - This sequence omits "AGC". This deletion causes a frameshift.
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AGC TCG - This sequence has deleted "TTA". This also causes a frameshift.
So, the sequences that exhibit a frameshift mutation through deletion are "TTA TCG" and "AGC TCG".
If only one response can be selected and considering typical frameshift definitions, the best choice reflecting a clear frameshift due to deletion would be "AGC TCG", because it retains the structural integrity at the start while causing a complete loss of the second codon "TTA", skewing the reading frame dramatically.
However, without clarification if only one response is warranted or not, it can effectively be stated that "AGC TCG" is the clearest option for exhibiting a frameshift mutation through deletion.
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