Horizontal gene transfer in yeasts

Horizontal gene transfer (HGT), defined as the exchange of genetic material other than from parent to progeny, is very common in bacteria and appears to constitute the most important mechanism contributing to enlarge a species gene pool. However, in eukaryotes, HGT is certainly much less common and some early insufficiently consubstantiated cases involving bacterial donors led some to consider that it was unlikely to occur in eukaryotes outside the host/endosymbiont relationship. More recently, plenty of reports of interdomain HGT have seen the light based on the strictest criteria, many concerning filamentous fungi and yeasts. Here, we attempt to summarize the most prominent instances of HGT reported in yeasts as well as what we have been able to learn so far concerning frequency and distribution, mechanisms, barriers, function of horizontally acquired genes, and the role of HGT in domestication.