Wednesday 24 March 2010

Remembering Ada: Professor Kay Davies

Considering her importance in CC&S, it would be very rude not to take part in Ada Lovelace Day, a celebration of inspiring women in science and technology. A lot of people are going to ignore the straight science and go right for the tech side of things, so I'm going to be as contrary as ever and talk about a female scientist who had a great deal of influence on me.

Professor Dame Kay Davies was the first woman biomedical scientist I can remember seeing on TV. In the 1980s there was a superb documentary about her work on Duchenne Muscular Dystrophy (DMD), a very severe genetically inherited disease that affects mostly boys. Apparently normal babies slowly lose muscle function as they grow older, dying by their early twenties as a result of complete paralysis. I can't remember who made the documentary; it may have been Horizon (before its criminal dumbing down), but it could just as easily have been QED or the much missed Equinox on Channel 4 (back before the channel gave in to reality TV hell). What I do remember is the blonde powerhouse driving forward the research into this deadly disease. She was smart, she was determined and she was making a difference; what more could a female proto-scientist want in a role model?

And she was up against quite a challenge. Professor Davies developed a test that would allow prenatal diagnosis of DMD, but actually hunting down the gene involved was no easy task. In the 1980s, molecular biology techniques were crude and laborious by current standards and usually involved playing around with tiny bits of DNA and lots of radioactive material. Still, her team got there in the end and the reason why it had been so hard to pin down the gene became apparent.

All of the genes in your body code for proteins, essential molecules that serve a myriad of purposes, from making up your hair and fingernails to digesting your dinner. Each gene is split into useful coding regions (exons) and filler non-coding regions (introns), but overall most genes aren't that big. Except for the Duchenne gene, which turned out to be huge, the largest known human gene, spread across vast distances of the X-chromosome which carries it. So big, in fact, that there is another entire gene hiding inside one of Duchenne's introns. Just to add to the numbers, the Duchenne gene is almost 2.5 million bases long (a base is the building block of DNA), has 79 exons, equating to approximately 4,000 amino acids (the building blocks of proteins). To make matters worse, those exons can be put together in slightly different ways to give lots of slightly different proteins that all have slightly different jobs. So you can see why it was such a task finding and sequencing that DNA a few hundred bases at a time.

Gene hunting in and of itself is very useful as it allows the development of screening tests, but unless you understand what the protein that gene makes is doing, you're still far from a solution. Even though we've sequenced the entire human genome as part of the Human Genome Mapping Project (1990 - 2003) we still don't know what most of those gene products are doing; we can read the book, but we don't know what it means. There's still is no cure for Duchenne Muscular Dystrophy, but thanks to Professor Davies' work, our understanding is much greater. Her continuing quest to crack the secrets of the gene will hopefully one day result in a treatment that will prevent the devastating effects of DMD.

So there we have it, my small tribute to Professor Dame Kay Davies, Fellow of the Royal Society, Governor of the Wellcome Trust and inspiration to molecular biologists everywhere, whatever sex they might be.

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