Commercial probes will be discussed in this course. Home brew probes are beyond the scope of the course and will be addressed in an advanced course.
Commercial probes may be provided in a buffer that contains formamide which will cause the probe to remain single stranded. For these probes, you do NOT have to denature (heat) the probe before applying it to the target area on the tissue. Other probes may be provided as a double stranded probe and you will need to denature the probe before applying it to the tissue to ensure that a single strand is available to anneal to the DNA in the tissue.
Hybridization is the process by which the DNA strand in the human tissue is "annealed" with the probe DNA. The DNA probe is applied to the targeted area of the slide and incubated at 37° C in a humid chamber overnight. The humid chamber is needed so that the slide does not dry out overnight.