Yeast competence for exogenous DNA uptake: towards understanding its genetic component

The demonstration of spontaneous yeast competence shows that artificial transformation rests on naturally occurring cellular processes. Such natural competence is either biologically mediated or environmentally induced. For instance, wild yeast might be transformed through conjugation by cell-to-cell contact mediated either by Escherichia coli or Agrobacterium tumefaciens. Moreover, natural competence can be enhanced by mechanical and physiological mechanisms. On the other hand, artificial yeast competence is usually achieved by biological, chemical and physical manipulations. These eliminate or weaken natural obstacles blocking the way of the transforming DNA in order to mitigate its entrance into the cell (biological and chemical approach) or simply to bridge it by either electrical or biolistic force (physical). Thus yeast competence is controlled by intrinsic (genetic) and external (environmental) factors. Both intrinsic and external parameters affecting yeast competence were scrutinized leading to the identification of genes and biological processes participating in the phenomenon. Therefore natural yeast competence is a complex, quantitative genetic trait which may have allowed yeast to better adapt over evolutionary times.