Dapx

Australian-American researcher Elizabeth Blackburn and Carol Greider and Jack Szostak of the United States won the Nobel Medicine Prize on Monday for identifying a key switch in cellular ageing.
The trio were honoured for discovering how chromosomes are protected by telomeres and the role of an enzyme called telomerase in maintaining or stripping away this vital shield.After Blackburn's studies in 1980 on a single-cell organism known as Tetrahymena, or pond scum, she and Szostak discovered in 1982 that a unique DNA sequence in the telomeres protects the chromosomes from damage when the cells divide. In 1984, Blackburn and her then grad student, Greider, also identified telomerase, the enzyme that makes the telomere DNA.