What is the key characteristic of DNA fragmentation in Maxam-Gilbert Sequencing?

The key characteristic of DNA fragmentation in Maxam-Gilbert Sequencing is that the DNA fragment to be sequenced is radioactively labeled at the 5' end. In this method, the DNA is first labeled to allow for detection of the fragments that are generated through specific chemical treatments. By tagging the 5' end, the resultant fragments produced through cleavage can be easily identified during the separation and analysis steps that follow.

This labeling is crucial because it provides a way to visualize the fragments in later steps, typically using gel electrophoresis. The unique aspect of labeling at the 5' end in Maxam-Gilbert Sequencing is contrasted with other sequencing methods where 3' end labeling might be employed. This characteristic ensures that the specific fragments generated during the sequencing reactions can be accurately tracked and resolved.

In contrast, the other options do not correctly define the primary characteristic of this sequencing methodology. For instance, while chemical treatment does indeed generate cuts at nucleotide bases, the specificity and method of labeling are particularly notable in Maxam-Gilbert Sequencing. Thus, the radioactively labeled 5' end is critically relevant in the context of this sequencing technique.