United Press International - October 7, 2002
Charles Choi

This is the first time such "phylogenetic analysis" was used as evidence in a U.S. criminal trial.

"It's clearly going to be widely used in future," David Hillis, an evolutionary biologist at the University of Texas at Austin, told United Press International.

Gastroenterologist Richard Schmidt of Lafayette, La., was charged with the attempted murder-by-virus of nurse Janice Trahan. The nurse broke off a stormy 10-year affair with the doctor in July 1994. Three weeks later, prosecutors allege Schmidt injected his former lover with HIV-tainted blood, under the guise of giving his girlfriend a vitamin B-12 shot for her chronic fatigue.

The prosecution contacted laboratories in Michigan and Texas to trace the origin of Trahan's HIV infection. HIV's DNA sequences mutate rapidly, allowing the virus to resist drug treatments. This high rate of change means each HIV-infected individual has viruses distinct from any other patient's, Hillis said, yet genetically similar enough to determine ancestry and therefore virus transmission history.

Biologists use these same techniques to unravel the origin and relationships of species to form what they call trees of life.

Computer analysis of HIV from Trahan and dozens of infected individuals from Lafayette revealed that Trahan's HIV was related to viruses from a homosexual male patient under Schmidt's care who was infected in 1990. While Trahan had sex with six other men during her affair with Schmidt, none of them tested positive for HIV, and blood she donated until April 1994 was clean of HIV.

Furthermore, Hillis explained, Trahan's HIV strains were more closely similar to certain viruses in the patient than the viruses were to any other germ in the patient's body. This demonstrates clearly Trahan's viruses were descended from the patient's, Hillis said.

"When I went into graduate school, I had no idea of the new applications that would open up to phylogenetics," Hillis said. In Greek, phylogeny roughly means "the genesis of tribes," and phylogenetics studies the race history of organisms.

Schmidt was sentenced to 50 years at hard labor after he was convicted of attempted second degree murder in 1998.

"The method is good and the evidence is very strong," molecular evolutionist Walter Fitch of the University of California at Irvine told UPI.

In addition to helping forensic scientists solve cases, Hillis said these investigative techniques could help prevent the spread of epidemics and "trace the origin of attacks by bioterrorists." However, "there is the possibility of misuse of studies like this," he said. "People could start establishing blame for unintentional infection. I would hate to see the approach used by people to lay blame for their everyday illnesses."

Fitch added finding ways of reducing any possible error and increasing technique sensitivity "is always in order as scientific goals." Hillis said his team is doing just that by refining the algorithms used to determine ancestry. While the researchers on the Schmidt case only examined two genes -- one for HIV's viral coating, the other responsible for copying DNA -- Hillis added in the near future it should prove possible to analyze the whole genetic codes of viruses quickly for greater reliability.

This is not the only time phylogenetic analysis was used in criminal trials, Hillis said. It was first used in Sweden for a rape case and it is being used for a child abuse case in Arkansas where HIV is also involved.

The scientists described their findings in this week's Proceedings of the National Academy of Sciences.

(Reported by Charles Choi, UPI Science News, in New York)
021007
UP021005

Always watch for outdated information. This article first appeared in 2002. This material is designed to support, not replace, the relationship that exists between you and your doctor.

AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.

Copyright ©1980, 2002. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content. .