Hybridisation methods and “gene-chip” technology

In most of the methods described above, the specific site of a
mutation within a gene is not known until after DNA
sequencing has been completed. If the mutation is very
common, however, methods may be used that specifically
interrogate the site of the mutation. One of the simplest ways
of doing this is by using a restriction enzyme (see above);
however, this is not applicable in all situations.