Jeffreys, Alec John
Jeffreys, Alec John
Alec John Jeffreys is a geneticist who is best known for the introduction of DNA analysis to forensic science . He discovered one of the most important tools for identifying human beings, genetic fingerprinting. This procedure analyzes each individual's genetic code . Each human being has about 100,000 genes in the chemical form of deoxyribonucleic acid (DNA). The genetic information coded in these genes—ranging from the color of hair to disorders such as hemophilia—varies greatly between individuals. No two humans, except for identical twins, have the same genetic code. Genetic fingerprinting has been used to catch criminals, establish paternity, and detect gene mutations.
Jeffreys was born in Oxford, England, to Sidney Victor and Joan Jeffreys. He attended Luton Grammar School and Luten Sixth Form College. Jeffreys went to Merton College in Oxford to study molecular biology, achieving a B.A. in 1972. He also earned an M.A. and D.Phil. at Merton in 1975.
At the University of Amsterdam, Jeffreys worked with Richard Flavell, another British molecular biologist, studying mammalian globin genes. From there, Jeffreys moved to the University of Leicester, where he made his most important contribution to science, discovering the unique genetic fingerprint in 1984. He found that the number of times sequences in DNA repeated seemed to vary from individual to individual, and that these repeated segments of genes were unique to each individual—just like a fingerprint.
Jeffreys devised a way to capture the distinctive fingerprint of each person's repeated fragments in an x ray. By taking x rays, Jeffreys could see the repeated segments of DNA as black images on film. He had, in essence, created the first DNA fingerprint .
In 1988, scientist Henry Erlich added to Jeffreys's work when he developed a method of DNA fingerprinting so sensitive that it could be used to identify an individual from an extremely small sample of hair, blood, semen , or skin. Erlich's technique used Jeffreys's traditional method and combined it with a technique called polymerase chain reaction (PCR ), which was used to duplicate DNA and thus copy the genetic code. PCR multiplied the DNA from one single hair to an amount equivalent to that found in a million identical strands of hair. The amplified DNA was then used to obtain a DNA fingerprint.
Jeffreys continued to work in the field of genetic fingerprinting. In a famous 1989 murder case in Cardiff, England, PCR was combined with Jeffreys' traditional technique to extract and identify DNA from a miniscule amount of bone. A sample of bone from a skeleton found at an old house in Cardiff was sent to Erika Hagelberg, a scientist at the Oxford Institute of Molecular Medicine. Working with Jeffreys, Hagelberg found that the sample of bone had been in the ground so long and disintegrated so much that PCR could not generate the necessary lengths of DNA required for a fingerprint. So a different form of genetic fingerprinting had to be developed.
Working with Jeffreys, Hagelberg was able to find repeating DNA sequences other than the large ones usually present in a genetic fingerprint. They were finally able to show that the probability that the skeleton was Karen Price, a 15-year-old girl, was 99.9%. Two of Karen's acquaintances, Idris Ali and Alan Charlton, were put on trial for murder. It was the strength of the genetic evidence that finally sent them to prison, in Ali's case, for life.
At about the same time, Hagelberg and Jeffreys had been working on the new type of PCR typing to determine the identity of one of the most notorious war criminals of World War II, Josef Mengele. Known as the "Angel of Death" at Auschwitz, he sent thousands of Jews to the gas chambers as well as making thousands the subjects of medical research.
When the Soviets liberated Auschwitz in 1945, Mengele fled to South America. He was finally traced to a grave in southern Brazil in 1985. A sample of bone was sent to Jeffreys and, working with Hagelberg, he was able to identify a tiny amount of Mengele's DNA from the sample, which had been in the ground for six years.
The process of genetic fingerprinting can take as long as four to six weeks in a commercial laboratory today. Jeffreys made scientific history again in 1991 when he announced the development of a refined version of the test, allowing results to be obtained in as little as two days.
Jeffreys' technique of genetic fingerprinting has been used in a wide variety of ways, including to solve crimes like rape and murder, to identify the remains of soldiers, to identify people killed in Argentina by the military junta in the 1980s, and by biologists to protect endangered species. In a landmark study, Jeffreys and other researchers used the technique to assess the gene mutations apparent in children whose families had been exposed to radiation during the 1986 Chernobyl meltdown in the Ukraine.
Jeffreys is an international biomedical research scholar at the Howard Hughes Medical Institute, as well as working at the University of Leicester. Besides winning the Davy Medal from the Royal Society in 1987 and the Analytica Prize from the German Society of Chemistry in 1988, he became Wolfson Research Professor of the Royal Society in 1991.
In 2004 Jeffreys was awarded the Royal Society's Royal Medal "for his outstanding discoveries and inventions which have had major impacts on large areas of genetics. He is best known for the introduction of DNA analysis to forensic science, contributing not only the theoretical framework for application, but also the experimental method."
Jeffreys married Susan Miles in 1971. They have two daughters. His leisure interests include walking, swimming, postal history, and reading "unimproving novels."
see also DNA fingerprint; DNA sequences, unique; PCR (polymerase chain reaction).