A new selective agent for eukaryotic cloning vectors.

An aminoglycoside antibiotic, G418, has been shown to be an inhibitor of many pro- and eukaryotes at concentrations from 1-300 microgram/ml. A bacterial R-plasmid determinant that phosphorylates and inactivates antibiotic G418 can be introduced into yeast by transformation and expresses resistance to G418. It is suggested that this combination of antibiotic and dominant resistance mechanism may be useful in recombinant DNA studies as a cloning selection in eukaryotes.