SAN FRANCISCO - OCTOBER 05: University of California San Francisco scientist Elizabeth Blackburn speaks during a news conference after winning the Nobel Prize in Medicine October 5, 2009 in San Francisco, California. Blackburn shared the 2009 Nobel Prize in medicine with Carol Greider and Jack Szostak for their discovery of how chromosomes are protected by telomeres and the enzyme telomerase. (Photo by Justin Sullivan/Getty Images)
