DNA Fingerprinting
One in a Million DNA fingerprinting (the
use of a person’s DNA to identify
them) has become a hot topic in the field
of law enforcement as well as the
entire world. The controversy exists on
whether or not it should be admitted in
court as evidence at this time. Some
experts believe that the present technology
allows DNA fingerprinting to be
used in cases for positive identification (proof
that the DNA match was at
the scene of the crime) because of the extreme
unlikeness that a "tampered"
tissue cell could come up with an exact match.
The chances are stated to
be somewhere between one in ten million and one in ten
billion. Other experts
believe that since there is no current standard for labs
to test DNA samples
and there is a possibility of great human error in a very
complicated ordered
set (DNA) that a positive identification could be made on
someone who is far
from the actual perpetrator. Both sides believe that DNA can
identify a
person, they just disagree on whether or not that is possible at this
point
in time. DNA fingerprinting takes a sample DNA (victims, suspects, etc.)
and
counts the number of variable number of tandem repeats (VNTR) in a
person’s
DNA string. The repeats for four or five common repeating "gene
groups" are
counted and compared to a known sample (again the suspect, victim,
etc.) for
a match up. This may sound like scientists are only counting or four
or five
numbers when in reality they are counting on four or five sets of
many
numbers. The chances of similar numbers coming up in life (not the court
case)
are between one in a million and one in a billion. The experts in favor
of using
DNA fingerprinting now use the odds of one in a million having
similar enough
DNA strands to even come close to misidentifying anyone.
They believe that since
the contamination factor can come into play the
evidence should only be used to
identify for positive proof. The chances that
a contaminated sample could come
close to matching with a suspect’s sample
are even worse than the one in a
billion odds mentioned before. These experts
believe that using four or five
sets of numbers clears any doubt of
verification once and for all. The experts
who believe it shouldn’t be used
claim that our present technology disrupts
the accuracy of actual DNA
fingerprinting. They agree the odds of misidentifying
are slim, but they are
still too large to accept in a court of law. An example
they use is the
miscalculation factor in VNTRs. The difference between 109 and
119 is so
slim that it could be calculated as the same by today’s standards
when in
truth that may be a different person all together. The factor of human
error
is easy to see also, especially in the case of Jose Castro when witnesses
for
both the defense and the prosecution found the evidence analyzing
techniques
inadequate (it should be noted that the defendant did plead guilty
to the crime
of murder he was charged with and was found guilty). DNA
fingerprinting is at a
very impressive standard at this time for identify
people and there is no doubt
about whether or not it should be used in the
future. At this point I would
assume that a one in a million chance is enough
to be admissible in a court of
law for positive identification. I could not
blame a state for not admitting
it
either.