DNA Forensic Testing Industry Faces Challenge To Credibility

On Feb. 5, 1987, Vilma Ponce and her infant daughter were stabbed to death in their Bronx, N.Y., apartment. Police arrested a suspect, Joseph Castro, on whose wristwat they found a small bloodstain. The police took the evidence to Lifecodes Corp. in Valhalla, N.Y., where lab analysis convinced the company’s scientists that DNA retrieved from the blood on the watchface matched that of the dead woman. If true, this would have put Castro at the scene of the crime. Chances of the match bei

By | November 13, 1989

On Feb. 5, 1987, Vilma Ponce and her infant daughter were stabbed to death in their Bronx, N.Y., apartment. Police arrested a suspect, Joseph Castro, on whose wristwat they found a small bloodstain. The police took the evidence to Lifecodes Corp. in Valhalla, N.Y., where lab analysis convinced the company’s scientists that DNA retrieved from the blood on the watchface matched that of the dead woman. If true, this would have put Castro at the scene of the crime. Chances of the match being coincidental were 100 million to one, Lifecodes scientists later testified.

But late last summer, two and a half years after Castro’s arrest, a New York State Supreme Court judge, Gerald Scheindlin. ruled that those odds were not good enough to convict the suspect. Indeed, the judge ruled in a pretrial hearing, Lifecodes’ DNA test results were not even reliable enough to be used as evidence against Castro. The reason, according to the judge, was that Lifecodes "failed in several major respects to use the generally accepted scientific techniques and experiments for obtaining reliable results, within a reasonable degree of scientific certainty.”

While Judge Scheindlin did allow as evidence test results showing that the blood found on Castro’s watch was not Castro’s, he threw out results allegedly showing the blood matched that of the victim. Although Castro later confessed and is now serving a prison sentence, the Lifecodes testimony isn’t what put him behind bars.

The ruling came as a setback for Lifecodes Corp. as well as for the young and highly specialized DNA-based forensic testing industry that Lifecodes currently dominates. Prior to the Castro case, the seven-year-old biotechnology company had a 100% admissibility record for DNA from Quantum’s, but one can get an idea of how much this biotech venture takes in annually from the fees it charges and from the number of tests it conducts. According to Wexier, Lifecodes receives between 1,200 and 2,000 new cases each year, with the caseload equally divided between paternity and forensics tests. The cost of a paternity test involving three blood samples is $450. Forensic testing fees begin at $325 per sample. Lifecodes’ scientists and technicians who testify as expert witnesses in criminal cases charge $750 per day plus expenses.

Lifecodes employs a total of 125 people, about 40 of them scientists. Most are chemists, molecular biologists, and geneticists, who work on research projects aimed at improving and refining the company’s DNA analysis techniques. Some Lifecodes scientists also are involved in cancer research as the company expands its activity to cancer. diagnosis. However, most of the firm’s laboratory workers are not scientists, but technicians who analyze results of paternity and other tests, such as amniocentesis, that Lifecodes offers on a commercial basis.

Lifecodes is one of only three laboratories (Cellmark and the FBI operate the other two) in the country that perform forensics-based DNA fingerprinting tests. Over the past two years, the company has analyzed hundreds of samples from around the country. Its scientists have also testified as expert witnesses at hundreds of trials and hearings.

In the wake of the Castro case, however, scientists, legislators, and ethicists alike are calling for more stringent standards governing DNA forensics testing. They want a single set of guidelines for executing the fingerprinting tests and for interpreting their results.

According to Eric Lander, a mathematician and geneticist at Harvard University and the Massachusetts Institute of Technology’s Whitehead Institute who testified for the defense in the Castro case, rigorous standards for interpreting DNA results are especially necessary.

C. Thomas Caskey, director of the Institute for Molecular Genetics at Baylor College of Medicine in Houston, says the fact that Lifecodes’ test results were barred as evidence in the Castro case does not indicate that the company’s laboratory testing procedures were inadequate or that its interpretation of the results was flawed. Rather, Caskey says, it sorely points up the need for a single set of standards for forensic-based DNA profiling and for interpreting the results of such tests.

“Currently in the United States, there is no federal agency overseeing DNA fingerprinting,” Caskey notes. “As a result, there are different probes and slightly different methodologies being used. There are different methods of determining a DNA match and no standard set of calculations for determining the significance of a match.”

By contrast, in England, where the DNA testing technique was developed and the term DNA finger-printing coined by British scientist Alec Jeffreys, testing is regulated by a government agency.

Currently, there is a move toward similar regulation in this country. A committee of scientists is preparing a report on DNA fingerprinting for the Office of Technology Assessment, which is slated to submit the document to Congress before the end of the year. Heading up the committee are Caskey and Lander.

The National Academy of Sciences (NAS) is also looking into DNA fingerprinting, according, to Oskar Zaborsky director of the academy’s board on biology. Later this month, NAS will begin a 14-month study on molecular biology testing techniques and the social, legal, and ethical issues surrounding them, Zaborsky says, noting, however, that NAS has not yet appointed a committee.

It’s more than likely that any study of the DNA fingerprinting issue will be a long-term project. The primary reason is that the technology involved is relatively new and will continue to evolve as new commercial applications develop.

To illustrate this point, Ivan Balazs, a molecular biologist and geneticist and Lifecodes’ director of identity testing, says that just two short years ago, “we weren’t able to do the same things we do today. At the time that [the Castro case] test was done, we didn’t have the same controls in place that we have today. That doesn’t mean we were wrong. In fact, in the Castro case, we were proven right,” he emphasizes. (On Sept. 15, 1989, Joseph Castro pleaded guilty to murder, admitting that the blood on his watch was that of the victim, Vilma Ponce.)

As genetic testing technology evolves, so too will additional questions of ethics and social responsibility. Some of these questions have already surfaced. Who, for example, should have access to information concerning an individual’s predisposition to a lethal disease such as Huntingdon’s chorea? Other family members? Employers? Similar ethical questions surround the notion of databasing genetic information about convicted sex offenders.

The inevitability that such issues will surface and their potential for doing damage, at least in the short term, to a company whose livelihood depends on genetic testing, is not lost on Lifecodes’ senior vice president, John Winkler, a nonscientist who, among other things, is responsible for the company’s financial welfare. Given the volatility of questions about reporting results of inherited predisposition testing, Lifecodes abandoned its efforts in this area last year. It is now focusing its research and development on DNA probe technology for cancer diagnosis.

“Testing for inherited predisposition is an area where public policy has not yet been formed,” Wrnkler says. By contrast, he adds, “With cancer, it’s no problem.” When too, there are financial considerations, Winkler says.

“Predisposition-type things are generally very, very low incidence, which means there is a very small market. The way to do the test is inherently very expensive, because it basically amounts to a family study. To make the test affordable and informative, the gene that causes the [inherited] disease must be found, and right now, there are only three diseases in which the gene has been found.”

While Lifecodes pursues alternate market outlets for its finger-printing analysis techniques—now, for example, the company is concentrating on supplying other laboratories, including the FBI’s, with DNA testing kits containing all of the necessary enzymes, probes, and other agents to conduct the tests— the question of how the technology can best be forensically applied remains. In the absence of an answer geneticist Lander has warned that this should not dissuade scientists from pursuing the technology.

“As in the early stages of any new technology ... there is an urgent need for the scientific community to agree on clear guidelines for the procedures and standards needed to ensure reliable DNA fingerprinting,” Lander recently wrote in a commentary in Nature (339:501, 1989). This is especially true in the forensic applications, according to Lander, who. says that “at present, forensic science is virtually unregulated—with the paradoxical result that clinical laboratories must meet higher standards to be allowed to diagnose strep throat than forensic labs must meet to put a defendant on death row.”

Julia King is a freelance writer based in Ridley Park,Pa.

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