We are grateful to Linda Lutfiyya and Linda Riles from the M. Johnston lab for protocols and guidance in all aspects of yeast handling, gene disruptions, colony PCR and RNA preparations. We would also like to thank Skip Fournier, Jingwei Ni, Dmitry Samarsky, and Ted Maden for helpful discussions and sharing of unpublished observations. Thanks to Steve Johnson and Linda Lutfiyya for careful reading of the manuscript. This work was supported by NIH grant number R-01-HG01363 and by a gift from Eli Lilly.