The main principles that underly the use of nucleic acid probes for in situ hybridization are summar- ized. These include probe design, target preparation, hybridization formats and conditions, and signal:gener- ating systems. These principles underly the specific protocol that is described, namely the use of an akaline phosphatase-labeled cloned sequence of the alphoid repeated DNA family as a centomere probe for human chromosomes. Index Entries: In situ hybridization; centromere; chromosomes; nucleic acid probes.
