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.
  
  

	Fundamentals of Cell Function
	Cloning DNA
	Libraries
	Screening Libraries
	Gene Expression
	Elimination of Gene
	Interactions with Other Proteins