This research program is based on somatic cell genetic approaches to characterizing cell membranes and cellular traits relevant to transformation, with particular objectives in the areas of chromosome -mediated gene transfer, somatic mutagenesis, and membrane mutants. Conditions for transfer of ouabain-resistance and HPRT plus genetic markers between established human cell lines will be optimized, the properties of transferents will be characterized, and transfer capability will be extended to normal diploid recipient cells as possible. Mutagenic efficiency of simple alkylating agents in repair-deficient human mutant cells such as Xeroserma pigmentosum will be determined and synergistic interactons will be defined. Ouabain-resistant, ConA-resistant, and tunicamycin-resistant mutants will be studied with particular reference to pleiotropic properties and interactions, characteristics of revertants, and mutant expression in hybrid cells.