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Archiver > GENEALOGY-DNA > 2002-11 > 1036486323


From: Patrick Guinness <>
Subject: [DNA] Forensic Markers
Date: Tue, 5 Nov 2002 08:52:03 +0000


At 3:21 pm -0500 4/11/02, John F. Chandler wrote:
>For example, what if Easton's
>medical condition has been exaggerated? What if someone deliberately
>planted a specimen from Easton at the crime scene or substituted one
>somewhere along the route to the forensic lab? What if the specimen
>was accidentally contaminated? What if the lab botched the test, or
>somebody miscopied the results (and nobody caught the error)?

Yes, all that was possible, but the FSS (database) agreed that it was
an 'adventitious' match at 7 loci to one of their 70,000 crime scene
samples. The FSS said a 37m-to-one chance. It was in all the
newspapers.

They had double-checked at 7 loci, and there was a match between
Easton and the burglar.

Easton's result had been on file for some years. He had had a row
with his wife but was not charged, yet his DNA results remained on
file. In such cases in England the file is supposed to be destroyed
if no charges are brought, resulting in a conviction - they must have
just 'forgotten' to remove his file.

Yet he was arrested and hauled before a court near Manchester, over
100 miles away. Bail would not have been a problem. Tested again at
10 loci (SGM+), he did not match the burglar, and the case didn't
proceed. No official apology, so he's suing.

Look, I'm well aware that this was a very rare case - but if it can
happen (correction, *has* happened) at 7 loci against 70,000 samples,
and then I see that an American Govt website say that a 5 loci match
is 'beyond reasonable doubt', I'd be just a little concerned.

How many ignorant defendants in the USA / anywhere would know to ask
for tests at another 20 loci? The long odds would be mentioned by the
police at questioning. I'll bet many would sign a confession and do a
plea bargain.


At 3:21 pm -0500 4/11/02, John F. Chandler wrote:
>In real
>life, a million-to-one shot is considered "eliminated".

Yes - but retesting at more loci is the only way out. It worked for Mr. Easton.

PG

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