Picture

From hair cells to a prison cell
  
Mitochondrial DNA procedure offers prosecution breakthrough

A new DNA testing technique recently provided prosecutors in Hamilton County, Tenn., with the evidence to convict a man in the rape and murder of a 4-year-old Chattanooga girl, marking the first time the procedure was used in a criminal trial in the United States.

The technique, which analyzes the mitochondria, or the cytoplasm, of DNA cells and which can be used to examine hair, bone, teeth and nails, was used in the prosecution’s case against Paul Ware, 27, who was found guilty of felony murder on Sept. 4 in the 1994 killing of Lindsey Green.

Ware was sentenced to life imprisonment without parole later the same day, and he could yet receive an additional 15 to 25 years in prison for each of two convictions for child rape, according to Lee Davis, the assistant prosecutor who won the conviction against Ware. “The life-without-parole statute in Tennessee is in addition to the typical life sentence, so he is statutorily ineligible from ever being released from prison,” he said.

Davis told Law Enforcement News that a crucial component of the prosecution’s case was the evidence gleaned from mitochondrial DNA testing, which analyzes genetic material inherited from the mother. “In this particular case, we had not enough to do RFLP [restriction fragment length polymorphism] or PCR [polymerase chain reaction] analyses, we had no saliva, we were left with hair  a small pubic hair found in the girl’s throat that was linked to Ware,” the prosecutor said. “The mitochondrial DNA sequencing showed that it was consistent with his DNA.”

After Davis learned that the FBI was close to approving the method for use in forensic evidence-gathering, he asked that Ware’s trial be postponed from April to August. “I was in Washington talking to people from the FBI and told them we needed every available resource they had for this case. They told me about this process that might be coming on line…. We picked the trial date in August, hoping it would come on line. Fortunately, it did this summer.”

Ware was drunk when he went to the home of a friend, where he planned to spend the night, Lee said. The victim, who had been left with two other children in the care of a male baby-sitter, was sleeping in a back bedroom where Ware also decided to sleep. Her body was later found near Ware in an adjoining utility room after her alarmed parents picked the locked bedroom door. The defense tried to suggest that the baby-sitter had set Ware up to take the rap for the death, which was ruled the result of mechanical asphyxiation, but the DNA analysis cleared him, Davis said.

“One thing [the defense] didn’t anticipate is that one can tell whether a hair was naturally shed or pulled. The hairs in the bed and the hairs in her throat were naturally shed, making it consistent with a rape, as opposed to a baby-sitter pulling them from him and depositing them [at the crime scene],” Davis said.

The mitochondrial DNA technique, a protocol of which was approved by the FBI in June after six years of development, has been used by the Armed Forces Institute of Pathology to identify the remains of Vietnam War-era MIAs brought back from Southeast Asia. It also was used last year to positively identify the bones of Czar Nicholas II, who was executed during the Russian Revolution of 1917.

Because mitochondrial DNA analysis is so new, virtually no criminal laboratories in the United States are equipped to handle the technique, said FBI spokesman Paul Bresson, who said the bureau’s crime lab has processed mitochondrial DNA samples in “a handful of cases” so far.

Dr. Henry Lee, chief medical investigator of the Connecticut State Police and director of the State Forensic Laboratory in Meriden, said that mitochondrial genetic material is useful to criminal investigators because it is less likely to deteriorate over time. But he cautioned that the procedure is not a substitute for the more reliable RFLP or PCR analysis processes.

 “It opens up another dimension, but it’s not a substitute for conventional DNA testing,” he said. “But for those samples where you cannot find nuclear DNA, this is another way to check by looking for mitochondrial DNA. It’s not as informative as nuclear DNA because it only gives a profile of the mother’s gene traits.”

Lawrence Kobilinsky, a professor of biology and immunology at John Jay College of Criminal Justice in New York and a member of the doctoral faculty in biochemistry at the City University of New York Graduate Center, said the process is best used in cases where insufficient amounts nuclear DNA are present.

“When you look into nuclear DNA, you will find either one or two copies of a specific gene, where if you look at mitochondrial DNA, a gene will be present any place from 100 to 200 times, maybe even more depending on the type of cell,” he said.

Kobilinsky said that because information on genetic characteristics is limited to the mother in mitochondrial DNA testing, PCR is the best process to use. “If you have mitochondrial DNA, and it’s already present in a large amount, you can amplify it through PCR, and that should give you enough material to get your results…. It’s important to have this kind of test in the battery of tests [available to forensic investigators] so it can be used when the conditions are right, but it’s not going to be the common test for DNA.”

 

prev | next

people nation | home

Subscribe.
Published in Law Enforcement News
Nov. 15, 1996.
© 1996, LEN Inc.