Cytoduction preserves genetic diversity following plasmid transfer into pooled yeast libraries.

Much of our understanding of functional genomics derives from insights gained from large strain libraries including the yeast deletion collection, the GFP and TAP-tagged libraries, QTL mapping populations, among others [1-5]. A limitation of these libraries is that it is not easy to introduce reporters or make genetic perturbations to all strains in these collections. Tools such as Synthetic Genetic Arrays allow for the genetic manipulation of these libraries but are labor intensive and require specialized equipment for high throughput pinning [6]. Manipulating a diverse library en mass without losing diversity remains challenging. Ultimately, this limitation stems from the inefficiency of transformation, which is the standard method for genetic manipulation in yeast. Here, we develop a method that uses cytoduction (mating without nuclear fusion) to transfer plasmids directionally from a "Donor" to a diverse pool of "Recipient" strains. Because cytoduction uses mating, it is a natural process and is orders-of-magnitude more efficient than transformation, enabling the introduction of plasmids into high-diversity libraries with minimal impact on the diversity of the population.