Interactive DNA Testing Procedure
Requires the Macromedia
Flash plugin
The movie and the book, Jurassic Park, tell the story of a brilliant
-- if misguided -- scientist who builds a modern-day theme park
populated with real dinosaurs. In the story, scientists recover
tiny strands of dinosaur DNA from fossilized mosquitoes that have
been preserved for tens of thousands of years in amber. They isolate
the DNA, copy it and construct perfect dinosaur-DNA profiles - and
then, real dinosaurs. The idea that we can resurrect dinosaurs may
be science fiction, but the science that inspired the story is real.
A process called polymerase chain reaction - or PCR - is allowing
scientists to reach back in time and resurrect not dinosaurs, but
truth.
Truth is often unearthed, and science always revered, in the
laboratory of Dr. Edward Blake, just outside San Francisco. The
first thing you notice just outside his office is a miniature
scale that weighs two small cards: one of the cards reads, "The
opinions of forensic scientists," and it appears to be much
heavier than the other card, which reads: "The opinions of
lawyers." When prompted to comment on the display, Blake's
gravelly voice cracks into a laugh. "Most of us believe that
the opinions of lawyers aren't worth very much," he says,
"because lawyers believe that under the umbrella of advocacy
they can lie through their teeth." Blake's eyes are already
ablaze with indignation as he practically pants with passion.
"And they're not even ashamed to admit it."
Blake is a man of strong opinions. He's also one of the nation's
most respected forensic scientists, and the first to work with
PCR, the technique that inspired "Jurassic Park," and
in 1985, revolutionized DNA testing. "We're at the level
now," explains Blake, "where we have the holy grail
of genetic discrimination." Blake says this revolution in
genetic discrimination was like replacing a pair of blurry glasses
to study the stars with the Hubble telescope.
The exoneration of Earl Washington shows just how powerful modern
DNA-testing is. A police investigation, a confession and a jury
sentenced Washington to die. DNA analysis set him free. Peter
Neufeld of the innocence Project calls DNA "the gold standard
of Innocence" because it is much more reliable than all the
other kinds of traditional evidence - such as eyewitness testimony,
hair analysis, or statements from jailhouse informers. "This
is scientific evidence," says Neufeld, "that can prove
identity conclusively."
But some people worry that the reverence for science in general,
and DNA in particular, can go too far. Gary Close, the County
prosecutor in Culpepper, Virginia, where Earl Washington was tried
and convicted, worries that respect for science has been elevated
to "almost religious faith." Close does not dispute
that DNA offers investigators a powerful tool, "but criminal
cases don't rest solely on DNA," he says, "but on a
wide range of evidence." In the case of Earl Washington,
Close believes Washington's confession outweighed the DNA evidence.
Some, including the forensic scientist, Edward Blake, say that
represents the stubborn refusal of public officials to admit they
made a mistake and sentenced an innocent man to death. "The
only objective evidence [in the case] is the sexual assault evidence,"
argues Blake, "and that evidence has spoken as loudly as
any evidence could speak." And in this case, Blake says,
the evidence clearly demonstrated Washington's innocence and the
state's error.
But on the broader issue of DNA analysis as a final finder of
truth, Blake is more cautious. "It helps establishes a fact,"
he says, "and that's it." And fact, he argues, doesn't
always lead to the truth. Consider the trial of O.J. Simpson in
which prosecutors presented a wealth of credible DNA blood-evidence
that linked Simpson to the murder of his wife and her companion.
Simpson's defense team, which included Blake as an advisor, couldn't
challenge the DNA science, so they challenged how it was interpreted;
and accused police and prosecutors of tainting the evidence -
even planting it. Blake says the blood evidence in the Simpson
case was clearly an important component. "But when the entirety
of the case in compromised by the way the government conducts
its affairs," he says, "reasonable doubt raises its
ugly head." In other words, the case showed that in the hands
of skillful lawyers like Barry Sheck and Peter Neufeld, DNA is
just one piece of evidence among many.
Since the mid-1980s, DNA testing has led to a number of spectacular
exonerations of the falsely convicted. But as a prosecutorial
tool it has led to many more arrests and convictions. At the Virginia
State crime lab, which houses the nation's first and largest DNA
databank, Dr. Paul Ferrara says his staff averages almost two
"cold hits" a day - when they match DNA evidence from
a crime scene with the profiles stored in their computers. "It
happens daily now," Ferrara says with a good deal of pride.
During our visit, Ferrara takes us into a "codis room,"
where forensic scientist Bob Scanlon uses a computer to work on
an unsolved rape case from 1996 that hadn't been subjected to
modern DNA testing until now. Sperm from the victim produced to
a DNA-profile that's now being compared to nearly 200,000 profiles
in the databank. Scanlon watches rows of numbers fill his screen.
Then, as Ferrara leans over his shoulder, Scanlon points to one
set of figures that are flashing. "That's probably a good
hit," he says. This cold hit will provide a name of a suspect,
as well as probable cause that will permit police to seek an arrest.
Ferrara says cold hits like this also often lead to quick convictions.
"When confronted with a strong case that includes DNA,"
he says, "a lot of people recognize they're better off taking
a plea than fighting it."
The state of Virginia is expanding its DNA databank to make
it even more effective. Under a new law, the state plans to take
saliva-based DNA not only from convicts, but from everyone arrested
for a violent crime. Jerry Kilgore, Virginia's Attorney General
who sponsored the new DNA law, says it will enlarge the data bank
and give law enforcement officials a chance to catch violent offenders
more quickly. "It's a public safety issue," according
to Kilgore, who says the new law will provide "a better opportunity
to determine if we have a serial killer, or if we have someone
who has committed crimes over and over again."
Home
| Death Row Stories | Science
of DNA | Law & Politics
Inside Out | Credits
| WBUR
