Co-linearity of beta-galactosidase with its gene by immunological detection of incomplete polypeptide chains.

Many nonsense mutants that map in the beta-galactosidase structural gene produce material that forms precipitin lines when tested by double diffusion on agar against antiserum prepared from native beta-galactosidase. Relative sizes of the cross-reacting materia!s measured by sucrose density gradient centrifugation are the same as sizes calculated from genetic mapping of nonsense mutants. Orientation of the protein to its gene is also indicated.