beta-galactosidase (lacZ) Edited by Chang Zhu Bacterial plates --- X-gal Screening for insertion --- blue-white (lacZ) ONPG beta-galactosidase activity assay beta-galactosidase acitivity assay --- 96-well X-gal staining of cells X-gal staining in the fruitfly Beta-gal filter assay Staining of mouse embryo --- lacZ