Pioneering DNA Forensics
Pioneering DNA Forensics
Sir Alec Jeffries is the British geneticist who discovered the DNA fingerprint two decades ago. His accidental revelation made it possible to identify people by detecting variations in their genes, changing forensic science, criminal justice and paternity cases around the world. Jeffries is a research professor at the University of Leicester.
MICHELE NORRIS, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.
ROBERT SIEGEL, host:
And I'm Robert Siegel.
In London, forensic experts are still working round the clock to identify all of the 54 people who were killed in last week's bombings. So far they've identified 41 bodies. When we report on stories such as that one, we take for granted the idea that peoples' bodies can be identified with certainty, not just by their clothing or by their fingerprints, but by their DNA. We can also link criminals to victims or to evidence and we can link people to their biological relatives.
All this began just over 20 years ago in England. Recently, I spoke with the man who discovered the DNA fingerprint. He is Sir Alec Jeffries. He was subsequently knighted for his work. He is a geneticist at the University of Leicester, just as he was in 1984 when he was conducting a DNA experiment that had nothing to do with identifying individuals.
Sir ALEC JEFFRIES (University of Leicester): The last thing on my mind was identification and forensics and paternity cases and all the rest of it. What we were interested in doing back in those early days of human molecular genetics was just trying to find out some basic information about inherited variation in our DNA. And it was purely by accident in those studies that we generated, totally out of the blue, what proved to be the very first DNA fingerprint.
Sir ALEC: And that emerged. I remember it very clearly. This was a real eureka moment. It happened at 5 past 9 on the morning of Monday, the 10th of September, 1984. That was the--that split second in time when my life completely and utterly changed. So that very first DNA fingerprint, which I can see in front of me right now on the wall of my office--I still have the original--a very murky, grubby bit of X-ray film. On that we could see what appeared to be pretty variable and informative patterns of DNA. Purely by chance, we had a family group on there, one of my technicians and a mother and father. Not only could we tell those three people apart, but we could see how the technician's pattern was a composite of some of mum's and some of dad's characters.
And on that very first test, we just had a set of DNAs plotted at random really. So we had not only people, but I think a mouse and a rat. We had a baboon. We had a cow. We even had tobacco, believe it or not. And, to my amazement, not only did this work on people, it worked on absolutely everything else as well. It was--having seen this very first pattern, the penny dropped almost immediately. Within a minute I suddenly realized, `Wait a minute. We're looking here, potentially, at DNA-based biological identification.'
SIEGEL: Now this eureka moment, you had discovered something that you had not set out to discover?
Sir ALEC: Absolutely not. And I think if we had been charged with the task of inventing DNA fingerprinting--let's suppose some remarkably prescient funding agency two years previously had said, `OK, come up with a method for individualizing people using their DNA,' we would have been totally stumped. We wouldn't have known where to go. And this happens all too often in science. The basic discoveries then lead either directly or after a while to applications, but the driver behind the discovery is basic scientific curiosity, but not a desire to solve a particular medical or social problem. And that was certainly true for DNA fingerprinting.
SIEGEL: The first great arena of applying your discovery was forensic and also establishing paternity. I guess it remains as such today.
Sir ALEC: My feeling was that, yeah, this might have a specialist niche and will probably take 10 years before it's ever moved into real casework. I couldn't have been more wrong. Our first case--and this was following publicity of our first scientific paper on this--the write-up in one of the national newspapers in England was spotted by a lawyer who was representing a family trapped in an immigration dispute. So not paternity, not a criminal case; this is an immigration dispute. And, in fact, it was that case that we were asked to take on, which we did, which represented the very first time ever that DNA was ever used to sort out a problem of that sort.
SIEGEL: This was a boy from Ghana?
Sir ALEC: That's exactly right. Yeah.
SIEGEL: And the question that you answered with DNA was?
Sir ALEC: Well, the problem was that this family originally from Ghana--they were UK citizens--the youngest boy in the family went back to Ghana and then returned after a while to the UK on a passport that had been tampered with. So as he came back into the UK, this was picked up by the immigration authorities and the assumption was that the returning boy was a substitute either for a boy unrelated to the family or for one of the mother's nephews. So when we set out on this, I thought this is mission impossible. We'll never do this.
We did the DNA fingerprinting and the results suggest--I mean, absolutely stunning. I was amazed. Basically, we used three undisputed children in that family to reconstruct the DNA fingerprint of the missing father and then show for the boy in dispute that every genetic characteristic matched either mum or the missing dad. So we could rule out even the possibility that he was a nephew rather than the son to this woman with better than 99.999 whatever percent certainty. So that's what really started the whole story. That was the very first case. And a happy outcome: The British authorities dropped the case against the boy. He was allowed back permanently into the UK as a UK citizen, and the family was held together. Wonderful story.
SIEGEL: When the penny dropped and when it was clear to you that each of us, indeed, could be identified by something about our DNA and it could identify our relations to other people, did you think, `Oh, brave new world, life is going to get a lot better as a result of this. Or I've--there's a genie that just got out of a bottle that poses great harm to humanity.' What did you think?
Sir ALEC: I don't think I thought too much about that. I mean, I think I was much more concerned would anybody take a blind bit of notice in the work that we were doing. Once the genie was out of the bottle, what it was being used for--for example, our immigration disputes. This is a family threatened with being broken apart by a immigration dispute that we brought back together. Shortly after that, we were inundated with similar requests. Many, many families in the UK trapped in exactly the same sort of problem. This was science very clear societal good. And so that, in a way, sort of reassured me that this was science where the--yeah, I mean, all technology has an upside and a downside. The upside on this was strong; the downside was vague concerns where in the future possibly about Big Brother, civil liberties and all the rest. But, I think, if you look back then and look now at the totality of forensic DNA testing, it's absolutely for the good.
SIEGEL: Well, Professor Alec Jeffries, Sir Alec Jeffries, thank you very much for talking with us today.
Sir ALEC: It was my pleasure talking. Thank you.
SIEGEL: Alec Jeffries is a professor of genetics. He spoke with us from his lab at the University of Leicester. His discovery of the DNA fingerprint two decades ago made DNA profiling and testing possible.
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