Assays for Protein Expression - Detection of the proteins produced by transgenes are either based on antibodies specific for or on the enzymatic properties of the concerned proteins. Specific antibodies can be employed for a variety of immunological assays of which ELISA (Appendix 2.VIII) is the most rapid and convenient; some other assays are immunoblotting, radioimmunoprecipitation and immunohistochemical staining of tissue sections.

Assays of enzyme activities are usually applicable to scorable marker genes, which produce unique enzyme activities not found in the host, and are efficiently detected by using relatively simple procedures.