2009 Nobel Prize in Medicine
As cells divide, their chromosomes get shorter. This is because the DNA sequences at both ends of a chromosome, called telomeres, shrink in length every time the DNA is copied. James Watson, who had resolved the structure of the DNA molecule along with Francis Crick, pointed out a perplexing circumstance. The established theory of how DNA was copied before cell division could not be reconciled with the fact that DNA strands have ends. Try as they might, the researchers could not figure out how the DNA strands could be copied without losing bits off their ends. After repeated replication and shortening, the genes and cells would be damaged.
This quandary, known as the end-replication problem, was elegantly resolved by the discoveries of Elizabeth H. Blackburn, Carol W. Greider, and Jack W Szostak who were awarded the 2009 Nobel Prize in medicine. Their team discovered the enzyme Telomerase which stops shortening by adding base pairs that grow short telomeres.
All human DNA contains the instructions for making telomerase, but in most cells these instructions are turned off. So-called Telomerase Activators, as the name implies, turns on these enzymes in cells
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