DNA ‘fingerprinting — the ultimate evidence?

Press, 1 December 1987, Page 38

DNA ‘fingerprinting — the ultimate evidence?

By MICHAEL ZIELENZIGER of Knight-Ridder Newspapers ? Tacoma, Washington Did a bus driver, Alan. J. Haynes, rape a 57-year-old woman whose Alzheimer’s Disease leaves her unable to testify? A slender thread of genetic evidence will convince a jury of his guilt, prosecutors say. There are no witnesses and no fingerprints to the alleged rape in June, and the defendant cannot even remember the incident. Yet, by using sophisticated new techniques in microbiology, prosecutors intend to prove that the pattern of DNA chromosomes in Haynes’ blood matches the DNA found in the victim’s stained undergarments. If accepted by judge and jury, this revolutionary technique in forensic identification could give police a tool far more powerful than fingerprints when they search for physical evidence at crime scenes, experts say. The technique also offers new hope that unsolved

crimes some day might be closed. . “It’s absolutely the biggest thing that’s ever happened in forensics,” said; Dr Carole Jenny, director of the Sexual Assault Centre in Seattle and an advocate of DNA testing. “It’s DNA that makes everybody unique." But some defence attorneys and forensic experts argue that prosecutors are moving too quickly to bring DNA matching techniques into court, long before the reliability of the tests has been demonstrated clearly. “I’d be reticent to use (DNA matching) in court right now. I don't Know that it’s foolproof,” said Bruce Budowle, aresearch chemist studying the issue for the F.8.1.’s forensic research and training laboratory in Quantico, Virginia. “We’re optimistic about the scientific technique, but we don’t have enough data yet to defend the procedure in court.” At issue is the reliability of tests, which match small samples of blood, tissue, saliva or semen at a crime scene to the Deoxyribonucleic Acid,, or

DNA, of a suspect, DNA, the double-helixed molecule that Is the building block of human anatomy, contains the genetic code that transmits a person’s hereditary patterns. By using enzymes that slice DNA molecules at specific points in their structure, scientists have learned to create a “band pattern,” much like the “bar code” on supermarket products, to represent the unique character of an individual’s DNA. “These are very slender threads, but the length of the band varies from person to person,” said Laura McNally, a researcher at Lifecodes Corp, a laboratory that says it matched DNA in the semen recovered from the victim with the DNA in Haynes’ blood. The test also can prove absolutely that a suspect did not commit a crime, Ms McNally said. "Our test protects the innocent, too. With this DNA test, we can say that either he did it or he didn’t.” If widely verified by others, this DNA fingerprinting technique would be a “quantum leap forward” in the ability to narrow a suspect to the source of evidence, according to Edward Imwinkelried, Professor of Law at the-University of California and an ex-

pert on forensic evidence. He said proponents claim that the odds of two DNA patterns matching are one in three trillion. With conventional fingerprints! the odds of two pairs matching are said to be one in 64 billion. In spite of the F.8.1.’s .caution, however, prosecutors are rushing to use the DNA test to prosecute cases that once would have been difficult, if not Impossible, to put before a jury. In Orlando, Florida, a jury convicted Tommy Lee Andrews, aged 23, in a rape case in which DNA matching was the sole method , of tying the defendant to the attack. “Without the, DNA I don’t think we could have gone to trial,” said Tim Berry, an assistant state’s attorney who said he is a “true believer” in the procedure. "I haven’t heard, a single legitimate question raised about its reliability,” Mr Berry, a former policeman, said. “It’s a technique which has been used in the scientific community for a decade.” He said police Intend to reopen an eight-year-old murder investigation because of advances in DNA testing. But not all juries are easily convinced.

Last mqnth, in a different rape trial before the same judge, U. jury was unable to' decide Andrews’ guilt> Innocence bsaed on similar DNA evidence. The foreman of the jury later said he couldn’t Y*;decide whether (he DNA testing was conclusive because it is “new science” : s Peter Mair, a former Federal prosecutor how in private practice, said the DNA tests should not be accepted iri a trial because no one has done the “comprehensive research”; needed to determine- how probable it would he for different individuals to'share similar DNA “bandpatterns." Nevertheless, California and Washington states already are launching pilot programmes to teach DNA fingerprinting skills to crime labs, and advocates such as Dr Jenny expect that some day soon a national DNA library will keep records on hundreds of thousands of people. “We used to be pleased saying there was a 97 per cent chance we got the right guy,” Dr Jenny said. “With this new technology, we’ll be able to say, . ‘there’s a one in a billion chance you made a mistake.’ That will be the norm.” ' : Y'