Final answer:
The question pertains to how a revertant can occur when a mutation induced by an acridine-like intercalating agent is treated with the same compound. This is possible by the insertion or deletion of nucleotides which can restore the original DNA sequence or reading frame, thereby potentially reversing the mutation.
Step-by-step explanation:
The question is about a particular acridine-like compound that induces single insertions in DNA, which can cause frame-shift mutations. Such a compound operates as an intercalating agent, which by slipping between the DNA base pairs, distorts the DNA helix and often leads to insertions or deletions. When a mutation caused by this compound is treated again with the same compound, the initial insertion may be counteracted by another insertion or deletion, which potentially leads to a revertant, or a sequence that is functionally equivalent to the original unmutated sequence.
This concept is analogous to experiments where other forms of mutation induction and reversal have been observed, such as Crick's work with bacteriophages, where a third nucleotide insertion could restore function. Similarly, in Beadle and Tatum's experiments, different classes of mutants in the arginine biosynthesis pathway were studied, which were identified by their growth response to supplemented media, illustrating that changes in nucleotide sequences have direct consequences on metabolic functions.
Thus, a mutation induced by a single insertion can be reversed or 'corrected' by a revertant mutation, due to the new insertions or deletions brought by the same intercalating agent during a subsequent round of DNA replication, which may restore the original reading frame of the gene.