Can DNA evidence be faulty?

I just read an article at LubbockOnline.com that said a man who had been sentenced to 25 years in prison for rape had to be pardoned because faulty DNA evidence was admitted during his trial. Can DNA evidence be faulty? I thought that DNA evidence was rock-solid and could not be questioned. If DNA evidence can be faulty, could it be that there are innocent men convicted of crimes they did not commit due to faulty DNA evidence? How does DNA become "faulty" in the first place? Are we certain that DNA evidence isn't just a big scam?
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So if DNA can be so easily contaminated and can so easily give incorrect results, why is it allowed to be used as evidence in a court of law? It seems rather unreliable to me.

Di'tagapayo

The method of using DNA sequencing to identify that this DNA sample comes from the same source as the other sample is as close to exact as is stating the chances for error is silly. Keeping that in mind there are lots of rules about evidence and what is permissible. There in lies the rub. The curious conditions that we humans live in where someone with the potential to manipulate evidence for personal reasons are why these rules are in place. Not as to the discovery of that reason just to rule out that it could be a factor. Two people must be present at all times when the evidence is exposed. This is because the chain of evidence requires no single person alone to be in a position to manipulate the evidence. If the defense can prove a break in this chain then the evidence becomes "faulty."
Case in point. I know of a case where the person that collected the urine sample was secretly dating one of the guys she received an evidence sample from. She switched the samples because she knew her sweetheart had been smoking marijuana recent to the incident . This was only discovered years later after the wrong person served out the sentence.
Allow me to get snarky if you will. There are really so many bad answers here by the unknowing, misinformed and CSI TV educated forensic neophytes that I'm practically agog. Continue you reading of scholarly works on the subject if your truly interested.
There are controls for the sample that indicate DNA contamination. It's goofy to think a turkey would be convicted of the crime because it's DNA was on the carving knife that was used in the crime and to carve the thanksgiving bird as well, noh?

Max Hoopla

More facts are needed here.

Robert P

Any kind of test conducted must be conducted by human beings and they are notoriously faulty. If the test in question was not done in the proper manner with the proper safeguards then the results would or could be incorrect. This is true in drug testing, pregnancy tests and all other tests of this kind. It must be done in a specific way and under specific procedures to be deemed unchallengable. DNA can be easily compromised even before testing if it is not handled and stored properly and the same contamination can occur during testing for the same reasons. In two words, somebody goofed.

Holographer

Every lab has an error rate. Also, some labs use outdated sequencing or comparison methods. "DNA analysis" is a complex field; it requires a lot of hands-on handling of sensitive evidence. There are plenty of opportunities to contaminate the evidence along the way, or for an analyst to reach an incorrect result.

Kael M

It can be contaminated but if they make a 100% match to the suspect then its pretty much a slam dunk.
DNA is better than eye witness accounts because they can be wrong, DNA done right never lies.

WhitÆ¸ÌµÌ¡ÓœÌµÌ¨Ì„Æ·

it can be faulty if tampered with...

Ayesha Z

if it was in a lab then HELL NO DNA is alway right and yes it can be conaminated easily but imguessing the police had it so it..... actually it can be but ummm...it doesnt change the persons identity!!! it might get bacteria in it but that doesnt change who the person is!!!...

best answer!!!please!!!:)

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