The development of genome-scale resources and high-throughput methodologies has enabled systematic assessment of gene function in vivo. Synthetic genetic array (SGA) analysis automates yeast genetic manipulation, permitting diverse analysis of ∼5,000 viable deletion mutants in Saccharomyces cerevisiae. SGA methodology has enabled genome-wide synthetic lethal screening and construction of a large-scale genetic interaction network for yeast. Genetic networks often reveal new components of specific pathways and functional relationships between genes whose products buffer one another or impinge on a common essential pathway. Because SGA analysis can be used to manipulate any genetic element linked to a selectable marker, it is a highly versatile approach that can be adapted for a variety of different genetic screens, including synthetic lethality, dosage suppression, and dosage lethality. This chapter focuses on a specific SGA application for high-resolution genetic mapping, referred to as SGA mapping (SGAM), which enables the identification of suppressor mutations and thus provides a powerful means for interrogating gene function and pathway order.