Abstract: Provided herein compositions and methods for producing isoprenoids, including squalene. In certain aspects and embodiments provided are genetically altered yeast and uses therefore. In some aspects and embodiments, the genetically altered yeast produce isoprenoids, preferably squalene. The genetically altered yeast may have alterations in the expression or activity of enzymes involved in squalene production, for example, acetyl-CoA carboxylase (or “ACCase”), HMG-CoA reductase, squalene epoxidase, and squalene synthase. One or more genes of a genetically altered yeast may be modified by gene repair oligonucleobases. Also are provided methods of producing squalene using a genetically altered yeast. The invention also provides squalene produced by genetically altered yeast.