Biography of Rudolf Jaenisch

Genetics research often concentrates on identifying minute differences in the genome that give rise to assorted phenotypes. However, a large part of genetic control lies not in the makeup of particular genes or intergeneic regions but in their epigenetic conformation. The modification of DNA or of chromatin can profoundly affect gene expression without causing mutations. Rudolf Jaenisch, a member of the Whitehead Institute and Professor of Biology at Massachusetts Institute of Technology (Cambridge, MA), has made enormous contributions to the understanding of epigenetic mechanisms. Jaenisch created the first transgenic mice that enabled researchers to study epigenetic control of genomic viral DNA and advanced the epigenetics field through the studies of knockout mice and, most recently, cloned mice.

Jaenisch's work has earned him numerous awards and recognition, including the first Peter Gruber prize in Genetics (2001), the Robert Koch Prize for Excellence in Scientific Achievement (2002), and the Charles Rodolphe Bruphacher Foundation Cancer Award (2003). In 2003, Jaenisch was elected to the National Academy of Sciences. In his Inaugural Article (1), published in this issue of PNAS, Jaenisch and his colleagues show that stem cells derived from cloned embryonic carcinoma cells do not have the potential to differentiate beyond additional embryonic carcinoma cells. The article stands in stark contrast to his team's recently published research involving melanoma cells (2). These findings suggest that, although genetic factors exclusively may control the phenotype of certain cancers like embryonic carcinoma, epigenetic alterations may play a crucial role in other cancer types such as melanoma.