The origin of DNA testing

The following is Uncle John's bathroom reader's Eureka Moment (Eureka moment month 1984). Alec Jeffreys, a 34-year-old geneticist, is working in the laboratory of the University of Leicester in central England.

An article in. More precisely, he was in the darkroom of the laboratory, studying an X-ray film soaked in the developing tank last weekend. X-rays are the result of recently discovered abnormal DNA sequences. Through this process, a row of black lines appeared on a piece of film, dotted with blanks in the middle-almost like a bar code. The X-ray he is looking at shows the DNA "barcodes" of three people: one is his technician and her parents.

Jeffries didn't know what he could get from X-rays-he just invented the process. He wanted to see the evidence of changes in a specific area of DNA between parents and daughters, but after looking at the vague dark and bright space for a while, he suddenly realized that he had found a way to judge whether people were related by blood, which was completely accidental. In an interview with the Guardian in 2009, he told reporters: "This is definitely an exciting moment." It was a dazzling flash. In the five minutes of prime time, my research career flew away in a brand-new direction.

Jeffries saw it in a blurry X-ray.

After that: 1) each of the three family members has its own unique "bar code", "2) the bar codes of all three family members are interrelated (this is meaningful because each of us takes our own DNA as the combination of parents' DNA), and 3) this relationship is obvious. Jeffries soon realized that his discovery would have an impact on the parent-child relationship. With this technology, you can prove whether someone is someone else's child with scientific certainty. Or whether they are closely related. This technology can also be used in criminal cases, where criminals leave blood or other biological evidence.

Jeffries obviously found something unusual, but how to deal with it? He believes that its application in the real world will definitely take decades. So he just continued to study the process he called "DNA fingerprinting" and tried to improve it. At the same time, he wrote a scientific paper entitled "Individual Specific Fingerprinting of Human DNA", which was published in the journal Nature in July, 1985, and published two weeks later.

He received a phone call.

Test case: father-son relationship

This call came from a lawyer in London. He told jeffries that she had read an article about his "DNA fingerprint" in the newspaper, and wondered if this phone could be used in the immigration case she was dealing with. /kloc-The son of a 0/3-year-old English Ghanaian woman went to Ghana to live with her separated husband for a while. When he came back, the British authorities did not believe it was him. They think the family is trying to smuggle others-perhaps his cousin-into this country with their son's passport, and they want to expel the boy. Can jeffries prove that the child is the woman's son? "

Jeffries agreed to give it a try. He took blood samples from his mother, three other children and boys and made DNA barcodes for each of them. He concluded that a boy must be a woman's son. Lawyers submitted evidence to the British Home Office, and although DNA testing has never been used in cases before, they are still convinced. The boy was legally accepted as the son of this woman and allowed to stay in this country. Not only that, British immigration officials also said that they would allow DNA testing to determine any future cases with paternity testing problems. The Home Office may not realize that it has turned the brand-new and not widely understood use of DNA testing into a legal procedure. 1983165438+1October, the body of Linda Mann, 0/5 years old, in Nalborough, Leicestershire (not far from jeffries's place of work)/kloc-was called.

Test case: guilty or innocent

, has been discovered. She was strangled. Three years later, in July of 1986, the body of Dawn ashworth, aged 15, was found in the nearby town of enderby. She was strangled, too The evidence obtained from two cases shows that the attackers in both cases have the same blood type.

Shortly after the second murder, Richard barker, a kitchen porter aged 17, was questioned by the police. During the trial, he seemed to know the facts of the crime that only the murderer could know. After his arrest, he confessed to the second murder. The police are convinced that he also committed the first murder, but he insists that it has nothing to do with it.

After hearing about the paternity test case discovered by jeffries, police investigators asked the scientist to help them identify buckland as the murderer of Linda Mann. Jeffries agreed to help. He extracted DNA from * * * left by two crime scenes, and DNA from Richard barker Lan's blood sample, and then tested them, made a bar code, and determined that there was indeed one person who carried out the two attacks ... except Richard barker Lan.

No one is more disappointed than jeffries. Years later, jeffries told the BBC: "As a local with a young family, I am as eager as others that our discovery can catch the murderer. We can't believe what we saw. We repeatedly tested our findings.

hunting dog

After leaving buckland, the police left no suspects, so they decided to try something they had never done before. At the beginning of 1987, they called to ask all male residents (about 5,000 men) aged 17-34 in Nalboro and Endebury villages to voluntarily undergo DNA testing. Some people object that this requirement violates their privacy almost like science fiction. But understandably, most people are distressed by the idea that a murderous killer may be among them, and they support this idea wholeheartedly.

Almost all 5000 men in this area volunteered to donate blood. Although jeffries's new forensic technology didn't solve the case directly, it finally helped catch the murderer. Someone heard a man named Ian Kelly in the bar. He boasted that someone had paid him to take blood samples in someone else's name. The police questioned Kelly and arrested a 27-year-old Lester Baker. His name is Colin Pitchfork. Pitchfork immediately pleaded guilty, and later confessed to * * * and murdered Linda Mann and Dawn ashworth. He was sentenced to life imprisonment of at least 30 years.

Sequela of

Christina and Andrew Sabah (mother and son in the father-son relationship case) are the first people in history to solve the father-son relationship case through DNA testing. Richard barker Lan was the first person to prove innocence with DNA, and Colin Pitchfock was the first person to prove guilt with DNA testing. The news of these events made headlines all over the world. In less than a year, DNA fingerprinting technology-now called DNA analysis-was applied in the United States, and a few years later, it was almost regarded as a standard part of forensic medicine all over the world. We should not only find out who doesn't know, but also make sure who doesn't know.

Jeffries is still a professor at Leicester University, although he is now called Sir Alec Jeffreys. 1994 was knighted by Queen Elizabeth II for "serving science and technology". He also won many other awards because he proved to be one of the most important scientific discoveries in modern times. This has brought him some well-deserved fame: "In fact, I get an email every two or three days," he said in 2009. "Children from schools, mainly from the United States, will say,' I want to do a project about a famous scientist, so I chose you.' I like this. I always answer.

There are some facts.

This may be basic for CSI fans, but after Jeffuer discovered this fact on the fateful Monday morning of 1984, he didn't know whether the DNA in the blood could be used in his process. So he did the only thing a good scientist could do: "I spent two days cutting myself in the laboratory and left blood." Then we tested the blood. "(Of course useful) jeffries's original X-rays-the X-rays mentioned at the beginning of the story and the bar codes of three family members-actually have the password 1 1. The other eight are made up of animal DNA, including a mouse, a cow and a baboon. If you want to know, DNA testing has the same effect on animals and humans. This article is reproduced with the permission of the readers of Uncle John's 25th Anniversary Bathroom. The behemoth of this book is full of incredible stories, surprising facts, strange news, little-known origins, interesting word games and everything else. Millions of loyal fans have been expecting the best-selling bathroom reading series in the world since 1987.

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