Genetics of somatic mammalian cells: biochemical genetics of Chinese hamster cell mutants with deviant purine metabolism.

Studies are presented on the biochemical genetics of 30 adenine-requiring mutants of the Chinese hamster ovary cell which were induced by mutagenesis and selected by the BrdU-visible light technique. Representative experiments conducted with these mutants include: hybridization with each other; hybridization with normal human cells; nutritional analysis; biochemical analysis with radioactively labeled intermediates; and measurement of reversion frequencies to wild-type phenotype occurring spontaneously and under the influence of selected mutagens. All mutants behave as if having point mutations. These experiments provide information relevant to the determination of dominant-recessive relationships, resolution into different complementation classes, localization of the human chromosomes which carry human genes required by the individual mutants, determination of the point of metabolic block for different mutants, and elucidation of the nature of the underlying DNA changes. These experiments illustrate the range of biochemical-genetic studies now possible with such a family of somatic mammalian cell mutants in vitro. Possible application to problems of human genetic disease are indicated.