Raw scientific research is speculative, difficult and frequently obscure. It can be hard for funders to justify ongoing expenditure when the results are often unclear.

On Christmas day in 1984, one such piece of blue-sky research yielded results.  Carol Greider, then a graduate student working under the direction of Elizabeth Blackburn, discovered an enzyme responsible for constructing a genetic sequence found on DNA chromosome ends, called telomeres, which protects the chromosome from damage.

This telomere sequence, maybe likened to book ends on a library shelf, holding together the genetic material packed into the chromosome.  The discovery pertains to the enzyme  which maintains these book-ends, and which  is a fundamental biological mechanism present in nearly all plants and animals.  Without it, cells would rapidly age and degrade.  They called their discovery “ telomerase”.

Significantly, rapidly dividing cells, such as in cancers have an overproduction of telomerase.

In their introduction to their award for the Nobel Prize in Physiology or Medicine, the Nobel Institute says, "Every cell in our bodies contains our entire genome, the blueprint for life, wrapped up within its chromosomes. Each time one of our cells divides to form two new cells, its chromosomes need to be perfectly replicated so that each new cell receives an exact copy of the blueprint. As early as the 1930s, long before the molecular nature of DNA was understood, people such as Hermann Muller and Barbara McClintock had noticed that the very ends of the chromosomes appeared to serve an important protective role. But what these ‘telomeres’, or end parts, actually were remained a mystery. "

According to Nature, "Telomeres themselves shorten with repeated cell division, making up a key part of the cell's ageing mechanism. Low telomerase activity and telomere shortening speed up ageing, whereas incessantly dividing cancer cells often have high telomerase activity and maintain their telomere length. Cancer therapies involving antibodies directed against telomerase are now being tested in clinical trials. "

The other key person in this process of discovery is Jack Szostak who, at the time, was experimenting on yeast in an attempt to create artificial chromosomes.  He found that his artificial DNA was rapidly destroyed soon after it was inserted.  A chance meeting with Blackburn led to their collaboration.

The two realised that something had to be working to keep the chromosomes from degrading.  "Carol and I hunted it down," says Blackburn. "We didn't stumble over it. The molecular behaviour of the ends of the chromosomes was screaming out that there was something going on, some hitherto unknown enzyme."

Szostak incorporated these telomere sequences into his own artificial mini-chromosomes.  Despite being in a different species, the telomeres protected the new chromosomes from degradation.

Most normal cells divide infrequently and their chromosomes are not at risk of shortening. Cancer cells, on the other hand, have the ability to divide infinitely and yet preserve their telomeres as a result of increased telomerase activity. It has been proposed that cancer might be treated by eradicating telomerase.

Some inherited diseases are now known to be caused by telomerase defects, including certain forms of congenital aplastic anaemia, in which insufficient cell divisions in the stem cells of the bone marrow lead to severe anaemia. Certain inherited diseases of the skin and the lungs are also caused by telomerase defects.

The Nobel Assembly at Sweden's Karolinska Institute, which awarded the prize, said: "The discoveries by Blackburn, Greider and Szostak have added a new dimension to our understanding of the cell, shed light on disease mechanisms, and stimulated the development of potential new therapies."

Both Greider, now at the Johns Hopkins School of Medicine in Baltimore, and Blackburn, at the University of California San Francisco, continue to focus on telomerase in their research. 

Blackburn achieved a small measure of fame while serving on then US President George W Bush’ Council on Bioethics from 2002 until she was dropped in 2004 after criticizing the restrictions on human embryonic stem-cell research imposed by president.

Szostak is now at Harvard Medical School in Boston, Massachusetts General Hospital and the Howard Hughes Medical Institute.  Dr Jeremy Berg of the U.S. National Institute of General Medical Sciences, which funded some of the research, says, "He is trying to figure out how he can make proto-cells and get them to copy their genetic material. That's almost literally creating life in a test tube."

"We had no idea when we started this work that telomerase would be involved in cancer, but were simply curious about how chromosomes stayed intact," says Greider.  "Our approach shows that while you can do research that tries to answer specific questions about a disease, you can also just follow your nose."

Interestingly, this is the first time that two women have shared a Nobel Prize (hence the title: women have two X chromosomes, and males a X and a Y) in the long  history of the awards.  Ada Yonath’s co-winning of the Nobel  Prize for Chemistry (with Indian-born researcher Venkatraman Ramakrishnan, and Thomas A. Steitz,) is also a first for three women being acknowledged in the Sciences in the same year.   Adding to the recognition, this year, of illustrious work done by women is the Nobel Prize for Literature awarded to Romanian-born Herta Mueller.