Screening libraries
Once a library has been constructed, a good assay is needed to detect and
isolate the one clone out of thousands or millions of clones in the library.
Assays
- Probe DNA. A radioactively labeled fragment of DNA, hybridizing via
complementary base pairing, can be used to detect a clone containing DNA sequence
similar to the probe.
- Functional assay.Several clones are often tested together (a pool
of clones) for ability to transform cancer cells in culture (or other suitable
functional assay). If a positive response is found in a pool, the researcher
goes back to the pool and tests each individual clone of that group to find
the one clone that contains the gene.
