James Alexander Thomson is an American developmental biologist best known for deriving the first human embryonic stem cell line in 1998 and for deriving human induced pluripotent stem cells (iPS) in 2007. Research Human embryonic stem cells [which are cells that reproduce over and over and over again until they eventually die. they are what other cells 'stem' from] can divide without limit, and yet maintain the potential to make all the cells of the body. This remarkable potential makes them useful for basic research on the function of the human body, for drug discovery and testing, and as a source of cells and tissues for transplantation medicine. In 1998, Thomson's Lab was the first to report the successful isolation of human embryonic stem cells. On November 6, 1998, Science published this research in an article titled "Embryonic Stem Cell Lines Derived from Human Blastocysts", results which Science later featured in its “Scientific Breakthrough of the Year” article, 1999. In spite of their great medical potential, however, human embryonic stem cells generated enormous controversy because their derivation involved the destruction of a human embryo. In 2007, Thomson's group (contemporaneously with Dr. Shinya Yamanaka) reported a method for converting human skin cells into cells that very closely resemble human embryonic stem cells. Published in Science in late 2007 in an article titled "Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells", the results garnered international attention for potentially ending the ethical controversy surrounding human embryonic stem cell research. Science later featured induced pluripotent stem cells in its “Scientific Breakthrough of the Year” article, 2008. Education Thomson graduated with a B.S. in biophysics from the University of Illinois in 1981. He entered the Veterinary Medical Scientist Training Program at the University of Pennsylvania, receiving his doctorate in veterinary medicine in 1985, and his doctorate in molecular biology in 1988. His doctoral thesis involved understanding genetic imprinting in early mammalian development under the mentorship of Davor Solter at the Wistar Institute. Thomson also spent two years (1989–91) as a postdoctoral research fellow in the Primate In Vitro Fertilization and Experimental Embryology Laboratory at the Oregon National Primate Research Center, and completed a residency in veterinary pathology at the University of Wisconsin–Madison (1991–1994). He joined the Wisconsin Regional (now National) Primate Research Center on campus as its chief pathologist in 1995. There, he became the first in the world to successfully isolate and