The toolkit, a combination of techniques developed by the Hopkins researchers and others, starts with a collection of almost 6,000 yeast strains, each missing a different gene, and allows researchers to identify genes whose coupled elimination kills the yeast. Many laboratories are already using the "single knock-out" yeast collections, but postdoctoral fellow Xuewen Pan, Ph.D., found a way to protect the genetic integrity of the collection so that repeated experiments will provide the same results, regardless of when and where the experiments are conducted.
"Everyone in the yeast community has been using their own batch of yeast mutants, but the slow-growing mutants gradually accumulate extra genetic changes so they can grow faster," says Jef Boeke, Ph.D., professor of molecular biology and genetics and director of the HighThroughput Biology (HiT) Center in Hopkins' Institute for Basic Biomedical Sciences. "This potential for genetic impurity means that one person's batch of yeast is no longer exactly the same as someone else's. We went back to the original stocks of yeast mutants, in certain cases, so we know exactly what we have."
Human cells, with the exception of egg and sperm, have two copies of each gene, but yeast are content with either two copies of each gene or just one. Libraries of the almost 6,000 yeast mutants have just one copy of each gene, so there's no back-up for a missing gene that leads to slow growth.'"/>