Dr. Rudolf Jaenisch

Jaenisch has focused on creating transgenic mice that enable his lab to study forms of cancer and neurological diseases that have long baffled researchers.

Jaenisch's first breakthrough occurred in the 1970s when he demonstrated for the first time that foreign DNA could be integrated into the DNA of early mouse embryos; mice derived from these embryos carried the foreign genes in all of their tissues. Subsequently, Jaenisch injected retrovirus into early mouse embryos and showed that leukemia DNA sequences had integrated not only into the mouse genome but also to its offspring. These mice were the first transgenic animals in history.

Jaenisch also is a leader in the field of therapeutic cloning, also called nuclear transfer, in which the genetic information from one cell is transplanted into an unfertilized egg from which DNA has been removed. When placed in a Petri dish, this egg develops into a blastocyst from which stem cells can be taken. Jaenisch's therapeutic cloning research occurs exclusively with mice, but he advocates using the same techniques with human cells in order to advance embryonic stem cell research. Conversely, Jaenisch opposes human reproductive cloning, in which the egg is placed not in a Petri dish but into the uterus of a female, in the hope that it will develop into a fetus.

Today, the over-arching goal of Jaenisch's lab is to understand what scientists call epigenetic regulation of gene expression. This refers to the biological mechanisms that affect how genetic information is converted into cell structures but that don't alter the genes in the process. Jaenisch's lab is also investigating epigenetic mechanisms for certain types of cancer and for brain development, where much of his work focuses on how conditions such as Rett Syndrome occur.

Jaenisch received his doctorate in medicine from the University of Munich in 1967. Before coming to Whitehead, he was head of the Department of Tumor Virology at the Heinrich Pette Institute at the University of Hamburg. He has coauthored more than 300 research papers and has received numerous prizes and recognitions including an appointment to the National Academy of Sciences in 2003