GreenScreen GC eukaryotic genotoxicity assay rapidly screens lead compounds. The assay system is designed for use early in drug discovery. In a recent study, 2698 proprietary compounds were tested, as well as 51 marketed pharmaceuticals. The yeast system was shown to effectively complement Ames-based results by detecting different but overlapping classes of genotoxic compounds and increasing the number of positives from 164 with the Ames II assay alone to 328 positive with either the Ames II or GreenScreen assays. After Ames II positive compounds were rejected, 40 proceeded through pre-clinical development, of which 30 were negative in both the in-vitro regulatory mammalian tests and GreenScreen. Gentronix44-161-606-7268www.gentronix.co.uk