Yeast genetic screens have been absolutely instrumental in our understanding of cell biology. Yet they remain tedious and oftentimes incomplete. Next generation sequencing on the other hand is fast and exhaustive. I have implemented a transposon-based approach combined with deep sequencing to define the complete set of genes that are essential for growth in a particular condition, in one go. The idea is to saturate the yeast genome with independent transposon insertions. Transposons cannot insert in genes that are essential in a given condition. Deep-sequencing of the transposon-genome junctions of the whole library identifies the locations that tolerate the presence of the transposon and allows to deduce those that cannot, revealing the corresponding set of essential genes. The strength of the method lies on the fact that it interrogates the entire genome at once and is readily amenable to multiple growth conditions for comparison. When used to compare different genetic backgrounds, it reveals genetics interactions. When applied to compare drug-treated to untreated cells, it reveals the set of genes conferring resistance or sensitivity to the drug. In addition to identifying essential genes, this method also generates informative alleles. For instance, transposon insertions can yield truncations of essential genes, allowing to map functional protein domains.
Our method thus allows to screen the yeast genome with an unprecedented throughput and resolution.