DNA: the double helix that changed the world

The molecular double-helix structure of DNA

On this day 60 years ago a scientific-research paper was published that would change the world. James Watson and Francis Crick revealed the chemical structure of DNA, the molecule that contains the genetic blueprint and drives inheritance.

For many years it was the stuff of scientists studying genetics and disease, but words and ideas such as genes and inheritance of traits have become part of common parlance.

The rapid growth in our understanding over the past 60 years, including the delivery of genomes for a range of species including humans, has affected all of us at some level. This knowledge has brought improved medical treatments, new drugs and better disease diagnosis. It has increased crop yields, is helping to raise the nutritional value of foods, and is helping to develop replacement tissues for worn-out joints. Here, three people working in different areas share their impressions of the discovery six decades on.

Rosita Boland Irish Times feature writer

My first encounter with DNA occurred long before I understood what it was. I am the only red-haired person in my family, and became aware as a small child that this was somehow odd. Neither the generation preceding me, my own, or the one now following me has a rib of red hair between them. But red hair, that recessive gene, is in there somewhere in my combined DNA of Bolands and Comers: some long-dead relative has passed it on to me.

I find it almost impossible to comprehend the fact that physical likenesses can turn up generations later in families. I sometimes look at my nieces and nephews and wonder am I looking at clues to our long-dead, and mostly unphotographed relatives: jigsaws of genetics. It makes me feel dizzy, as does wondering if abstract characteristics of a person, such as courage, aspiration, kindness, grace and curiosity, can ever repeat themselves in similar ways. Is that an unscientific thought? Who knows?

But mostly, when I think about DNA, I marvel at how it has transformed forensic science. It enables the possibility of a second chance for justice being sought, often long after the crime has been committed. Retrospective justice no longer depends on Victorian ad-hoc deathbed-type confessions. Even the infinitesimally tiniest pieces of us of our bones, blood, hair, skin or body fluids can now constitute vital crime-scene clues to those who know how to read them.

DNA makes time fluid. Three generations later, a nose can be repeated like a motif down a genetic line. And it has the power to reel a person back in, through decades, even through death, to face truth about previously unsolved crime. I can still hardly believe these facts. Its more like science fiction than the stuff of science.

Aoife McLysaght Professor in genetics at Trinity College Dublin The structure of DNA was once a mystery to be solved, but nowadays, kids might even have seen it in cartoons before they start school. Humans were once considered exempt from the rigours of natural selection, somehow separate and above mere animals, but today it is common knowledge that our DNA is almost identical to that of a chimp.

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DNA: the double helix that changed the world