When science comes to the courtroom in two pending rape trials here, the outcome may hinge not so much on police detectives as on DNA detectives. The trials, including one involving a former Juvenile Court officer, will be the first in West Tennessee to use so-called DNA fingerprinting. The controversial process of using genetic material to link suspects to crimes has been used several hundred times since it was first used in 1987 to convict an accused rapist in Florida. it has been used in solving paternity cases since the 1970's.
Criminal investigators say the cellular testing method is the greatest breakthrough since fingerprint identification was developed in the early 1900's. Although not yet as precise as comparing fingerprints, they say DNA testing can identify someone often with a 1-in-a-100-million chance of error or less.
But critics say the probability numbers are exaggerated and that often the chance of error may be as great as 1 in 128. They worry that jurors may be blinded by science and the result could be the conviction of innocent defendants. "It's far too young to be relied upon as heavily as it is," defense attorney Mark McDaniel said. "In the early 1900's they built a boat (the Titanic) that was supposed to be unsinkable. How many people lost their lives on the unsinkable boat?"
In any event, DNA in the courtroom appears here to stay. Although several trial judges have banned it as unreliable, most judges believe DNA fingerprinting has gained general acceptance in the scientific community and are allowing DNA in the courtroom. Last year the Tennessee legislature passed a bill allowing DNA evidence into courtrooms and directing Tennessee Bureau of Investigation to establish a DNA testing lab and a DNA data bank of convicted sex offenders to identify or eliminate suspects in future crimes.