title: Transformation-defective virus generation from cloned nondefective avian sarcoma virus.
mesh_terms: D001355:Alpharetrovirus / Q000235:genetics / Q000254:growth & development*; D000818:Animals; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D003673:Defective Viruses / Q000235:genetics / Q000254:growth & development*; D005814:Genes, Viral; D009154:Mutation