Ecologically driven competence for exogenous DNA uptake in yeast

Unlike prokaryotes, eukaryotic organisms do not seem to be equipped with natural cell process(es) designated for exogenous DNA uptake. However, it is barely known that under laboratory circumstances resembling wild fungal environment(s), at least some lower eukaryotes could become naturally competent for exogenous DNA uptake. Thus, apart from the known fact that non-manipulated cells of yeast Saccharomyces cerevisiae take exogenous DNA by conjugation with certain bacteria, there are also mechanical and physiological mechanisms enabling their transformation under environmental conditions. This clearly shows that lower eukaryotes are amenable to transformation without applying man-made technology (i.e., naturally). However, this topic failed to raise critical scientific interest. Therefore, this review aims to scrutinize the overall implication of the phenomenon stressing its fundamental and applicable importance. It also summarizes all axiomatic laboratory circumstances/vehicles hitherto known to provoke yeast competence naturally and critically discusses plausible mechanisms behind. Possible pathways underlying the phenomenon are emphasized and a unifying model is proposed. This story potentially spans several different research fields, from evolutionary genetics to genetic transformation technology.