Double mutations

The vast majority of genes in the yeast genome are non-essential suggesting significant functional redundancy. In the December 14 Science, Amy Tong and colleagues describe an approach for high-throughput synthetic-lethal analysis in yeast (Science 2001, 294:2364-2368).

They developed an ordered array of about 4,700 viable gene-deletion mutants and generated haploid double-mutants; they called this strategy synthetic genetic array (SGA) analysis. Tong et al. tested a query strain with a deletion in the BNI1 gene against the ordered array and identified 67 potential synthetic lethal/sick interactions; these included known and novel interactions. Multiple SGA analysis allowed them to construct a large genetic interaction network containing over 200 genes.

These interactions should identify functionally related genes and provide a framework for future phenotype analysis and probing the relationships between interacting pathways. The authors suggest that 300 SGA screens could provide an effective genetic scaffold to explore redundancy and...