New developments in mutagenicity screening techniques with yeast.

Abstract

Yeasts provide a useful and versatile tool for studying genetic phenomena. The genetics of Sacchlaromyces cerevisiae has been intensively studied for many years, and as a result considerable information has been accumulated. Excellent current and comprehensive reviews on the genetics of yeast are available (1, 2), including one that is particularly directed toward studies of deleterious genetic effects of chemicals (3). Yeasts are eukaryotic organisms and therefore contain a nucleus and cytoplasm containing various other differentiated organelles quite similar to other higher life forms (4). The genetic apparatus consists of at least 17 chromosomes in the haploid S. cerevisiae identified by genetic mapping (5). Thus the structural organization of the genetic information is analogous to that in other higher life forms. Equally important is the well-known life cycle in yeast which, genetically, provides for classical mitotic and meiotic functions such as those existing in differentiated cells of more complex multicellular organisms. Yeasts, as well as all higher life forms, contain extrachromosomal DNA which provides essential genetic in-