'''Synthetic Genetic Array analysis (SGA)''' is a [[high-throughput]] technique for exploring [[synthetic lethality|synthetic lethal]] and synthetic sick [[genetic interactions]] ([[Synthetic lethality|SSL]]).<ref name="H. Tong 2001">{{cite pmid|11743205}}</ref>. SGA allows for the systematic construction of double mutants using a combination of [[Recombinant DNA|recombinant genetic techniques]], mating and selection steps. Using SGA methodology a query gene deletion mutant can be crossed to an entire genome deletion set to identify any [[synthetic lethality|SSL]] interactions, yielding functional information of the query gene and the genes it interacts with. A large-scale application of SGA in which ~130 query genes were crossed to the set of ~5000 viable deletion mutants in yeast revealed a genetic network containing ~1000 genes and ~4000 SSL interactions.<ref>{{cite A. H. Tong et al., Global Mapping of the Yeast Genetic Interaction Network, Science 303, 808 (2004) pmid|14764870}}</ref>. The results of this study showed that genes with similar function tend to interact with one another and genes with similar patterns of genetic interactions often encode products that tend to work in the same pathway or complex. Synthetic Genetic Array analysis was initially developed using the model organism ''[[S.cerevisiae]]''. This method has since been extended to cover 30% of the S.cerevisieacerevisiae genome.<ref>{{cite pmid|20093466}}</ref>. Methodology has since been developed to allow SGA analysis in ''[[Schizosaccharomyces pombe|S.pombe]]''<ref>{{cite pmid|17893680}}</ref><ref>{{cite pmid|18931302}}</ref> and ''E.coli''.<ref>{{cite pmid|19160513}}</ref><ref>{{cite pmid|18677321}}</ref>.
[[Image:Yeast colonies array 1536 format.jpg|thumb|300px|Arrayed yeast showing synthetic lethal interactions. Synthetic lethal interactions are those pairs of colonies with reduced or no growth.]]
==Background==
Synthetic Genetic Array analysis was initially developed by Tong et al.<ref name="H. Tong 2001"/> in 2001 and has since been used by many groups working in a wide range of biomedical fields. SGA utilizes the entire genome yeast knock-out set created by the yeast genome deletion project.<ref> http://sequence-www.stanford.edu/group yeast_deletion_project/deletions3.html</ref>.
==Synthetic genetic array analysis general procedure==
Synthetic Genetic Array analysis is generally conducted using colony arrays on petriplates at standard densities (96, 384, 768, 1536). To perform a SGA analysis in ''S.cerevisae'', the query gene deletion is crossed systematically with a deletion mutant array (DMA) containing every viable knockout [[Open reading frame|ORF]] of the yeast genome (currently 4786 strains).<ref>http://www.openbiosystems.com/GeneExpression/Yeast/YKO/ </ref>. The resulting [[diploids]] are then sporulated by transferring to a media containing reduced nitrogen. The [[haploid]] progeny are then put through a series of selection platings and incubations to select for double mutants. The double mutants are screened for SSL interactions visually or using imaging software by assessing the size of the resulting colonies.
[[Image:Pinning robot.jpg|thumb|280px|right|Replicating yeast colonies during SGA analysis using a pinning robot]]
