The use of nucleic acid or gene probes as cloning or diagnostic tools has
proven to be a powerful technique for mapping, isolation, and manipulation of
genes. Their applications range from the identification of genes responsible
for inherited human disorders to the rapid detection and identification of bacteria
or other microorganisms in microbial communities. For example, oligonucleotide
hybridization probes complementing either small ribosomal
subunits, large ribosomal subunits, or internal transcribed spacer regions have
now been developed for a wide variety of microorganisms. The technique of
in situ hybridization of labeled DNA has allowed genes to be mapped to single
chromosomes and in many cases to a single chromosome band, promoting
significant advance in human genome mapping