The 2007 Nobel Prize in Physiology or Medicine has been awarded to Mario R. Capecchi, Sir Martin J. Evans , and Oliver Smithies “for their discoveries of principles for introducing specific gene modifications in mice by the use of embryonic stem cells.”

Many hypotheses about the biology of aging will be tested in knockout and transgenic mice, so this is a big one for biogerontologists. Congratulations, and thanks, to the winners.