Thank you CharonY! This helps me out a lot. As for the probe that binds to the target region, how long in bp would that tend to be? I suppose I assumed that the probes would be about the same length as primers, and although primers specifically bind to the target, they are clearly not enough to determine the identity sequence. However, they may be thinking of universal primers used to amplify the 16S region, for example, which are not designed to be species-specific and therefore not intended to identify the sequence.