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Selection as a Model Organism
When researchers look for an organism to use in their studies, they look for several traits. Among these are size, generation time, accessibility, manipulation, genetics, conservation of mechanisms, and potential economic benefit.

Saccharomyces cerevisiae's has developed as a model organism because it scores favorably on a number of these criteria.


 * As a single celled organism S. cerevisiae is small with a short generation time (doubling time 1.5-2 hours @ 30oC) and can be easily cultured. These are all positive characteristics in that they allow for the swift production and maintenance of multiple specimen lines at low cost.
 * S. cerevisiae can be transformed allowing for either the addition of new genes or deletion through homologous recombination. Furthermore, The ability to grow S. cerevisiae as a haploid simplifies the creation of gene knockouts strains.
 * As a eukaryote, S. cerevisiae shares the complex internal cell structure of plants and animals without the high percentage of non-coding DNA that can confound research in higher eukaryotes.
 * S. cerevisiae research had a strong economic driver, at least initially, as a result of its established use in industry (e.g. beer, bread and wine fermentation).

Genome Sequencing
S. cerevisiae was the first eukaryotic genome that was completely sequenced. The yeast genome database is highly annotated and remains a very important tool for developing basic knowledge about the function and organization of eukaryotic cell genetics and physiology. Another important S. cerevisiae database is maintained by the | Munich Information Center for Protein Sequences. The genome is composed of about 13,000,000 base pairs and 6,275 genes, compactly organised on 16 chromosomes. Only about 5,800 of these are believed to be true functional genes. It is estimated that yeast shares about 23% of its genome with that of humans.

Further Yeast Techniques
The availability of the S. cerevisiae genome sequence and the complete set of deletion mutants has further enhanced the power of S. cerevisiae as a model for understanding the regulation of eukaryotic cells. Synthetic genetic array analysis is being used to examine the complete set of double deletion mutants. Examinination of epistasis effects in the double deletion mutants will give important information about gene interactions

Approaches have been developed by yeast scientists which can be applied in many different fields of biological and medicinal science. These include Yeast two-hybrid for studying protein interactions and tetrad analysis.

Many proteins important in human biology were first discovered by studying their homologs in yeast; these proteins include cell cycle proteins, signaling proteins, and protein-processing enzymes. The petite mutation in S. cerevisiae is of particular interest.