For which condition would a lack of binding occur between probe and target during hybridization?

A lack of binding during hybridization is most likely to occur under too strict conditions. Hybridization involves the binding of a probe to its complementary target sequence, and this process is sensitive to various parameters. When the conditions are too stringent—such as having high temperature or low ionic strength—this can disrupt hydrogen bonding between the probe and target. Under such circumstances, even a small mismatch or less-than-ideal base pairing can prevent the probe from binding effectively.

On the other hand, perfectly matched sequences would typically facilitate binding rather than prevent it. Conversely, a too low temperature can allow binding to occur more readily, as it reduces kinetic energy, making it easier for the probe to associate with its target. High salt concentration can stabilize the binding by shielding the negative charges on the nucleic acid backbones, which increases binding affinity, rather than inhibiting it. Therefore, the emphasis here is on how stringent conditions can directly impact the success of hybridization, making it crucial for optimal binding efficacy.