DNA Technology Update

Imagine that the only evidence found at a murder scene was a few strands of
hair or a cigarette butt. Or, that investigators discovered skeletal remains
with all the soft body tissue deteriorated. Can a crime laboratory conduct DNA
tests on the hair or bone, or for that matter, on the saliva recovered from
the cigarette butt?

Soon, the answer to this question will be "yes." Currently, scientists are
working to develop DNA tests to allow for the forensic examination of hair
saliva, bone, teeth, and skin, in addition to the blood and semen analyzed
routintely today in DNA testing.

In most crime laboratories, scientists perform DNA testing through a process
known as the Restriction Fragment Length Polymorphism (RFLP) method. However,
the next generation of DNA tests will rely on the polymerase chain reaction
(PCR), a technique used to make millions of copies of DNA material to allow
for laboratory analysis of much smaller specimens than currently possible. In
addition to being more sensitive than the RFLP method, PCR-based tests provide
a more rapid means of characterizing biological evidence.

In 1993, scientists expect to complete validation studies on a technique
called Amplified-Fragment Length Polymorphisms (AMP-FLPS). This technique
combines PCR's ability to make many copies of DNA evidence with the resolving
power that comes with examining fragment length polymorphisms, the principal
strength of RFLP. AMP-FLPS will provide investigators with valuable
identification information not obtainable with current methods.

Using AMP-FLPS, scientists can perform DNA tests in a matter of days, rather
than weeks. And, there will be no loss in the ability to draw conclusions from
the evidence.