Rudolf Jaenisch produced the first transgenic animals in the 1970. In the 80’s and 90’s his lab made many contributions to the understanding of cancer, neurological diseases, and the role of DNA methylation in mammalian development using transgenic mice. The lab was one of three labs worldwide that reported in 2007 cells taken from mouse tails could be reprogrammed into iPSCs by over-expressing four master gene regulators. Later that year, the lab followed up by further manipulating iPSCs to treat sickle-cell anemia in mice, the first proof in principle of therapeutic use of such cells. In 2008, the lab reported that neurons derived from iPSCs successfully integrated into fetal mouse brains and reduced symptoms in a Parkinson’s disease rat model. The Jaenisch Lab focuses on understanding the genetic and epigenetic basis of familial and sporadic diseases.