The Surprisingly Imperfect Science of DNA Testing
June 24, 2015 6:46 AM Subscribe
You're arrested for murder. You didn't do it. But your DNA was found on the dead man's finger. How could that happen? The Surprisingly Imperfect Science of DNA Testing:
How a proven tool may be anything but. A longform story by Katie Worth, produced by Frontline, Fusion, and The Marshall Project.
Don't forget fingerprints! No one has ever studied how many points of matching are "enough," they just made up a number. And SURPRISE. Having lots of common matching points on your fingerprints is a part of being human!
Edit: Link
posted by evilensky at 7:50 AM on June 24, 2015 [8 favorites]
Edit: Link
posted by evilensky at 7:50 AM on June 24, 2015 [8 favorites]
that whole thing about certain officers being able to recognize suspects from shitty cctv footage will turn out to be fake too, just a bunch of fucking police bullsit.
Previously: A super-human ability to instantly recognise faces they barely know.
posted by andoatnp at 7:53 AM on June 24, 2015 [2 favorites]
Previously: A super-human ability to instantly recognise faces they barely know.
posted by andoatnp at 7:53 AM on June 24, 2015 [2 favorites]
Plus eyewitness testimony is inherently flawed.
posted by srboisvert at 8:14 AM on June 24, 2015 [2 favorites]
posted by srboisvert at 8:14 AM on June 24, 2015 [2 favorites]
" Studies by researchers at the University of Nevada, Yale, and Claremont McKenna College found that jurors rated DNA evidence 95 percent accurate and between 90 and 94 percent persuasive, depending on where the DNA was found."
Yet another problem with the jury system as constructed.
Meanwhile, police dogs are fairly ineffective.
posted by Matt Oneiros at 8:47 AM on June 24, 2015 [2 favorites]
Yet another problem with the jury system as constructed.
Meanwhile, police dogs are fairly ineffective.
posted by Matt Oneiros at 8:47 AM on June 24, 2015 [2 favorites]
I was an alternate juror* on a child molestation trial that came down to the victim's testimony on the stand**, several years after the event, which testimony differed from the statement the victim had given previously, and some DNA evidence. (There was also some time and place and opportunity evidence, undisputed; some photographs and testimony from a nurse, which could have been more clear.)
The public defender walked us through a lot of the above -- the relatively small number of loci available, the presence of other people's DNA in some of the samples, the age of the equipment, the outmoded procedures used in the analysis. I wasn't allowed in the jury room during deliberation, so I don't know what everyone else felt about what we'd seen, but I had gone into the courtroom pretty confident that the DNA was going to show us the answer and left feeling tossed into the dark, feeling around for something to hang onto.
The actual jurors deliberated for for two-and-a-half days (me and the other alternate cooled our heels in the jury room upstairs). They couldn't reach a decision, so the judge announced a mistrial and that was that.
-------------------------
* All of the duty; none of the deciding.
**The victim was still quite young at that time, and overwhelmed by the circumstances and the setting, and it was tough to watch from a few feet away for an afternoon and a morning.
posted by notyou at 8:47 AM on June 24, 2015 [1 favorite]
The public defender walked us through a lot of the above -- the relatively small number of loci available, the presence of other people's DNA in some of the samples, the age of the equipment, the outmoded procedures used in the analysis. I wasn't allowed in the jury room during deliberation, so I don't know what everyone else felt about what we'd seen, but I had gone into the courtroom pretty confident that the DNA was going to show us the answer and left feeling tossed into the dark, feeling around for something to hang onto.
The actual jurors deliberated for for two-and-a-half days (me and the other alternate cooled our heels in the jury room upstairs). They couldn't reach a decision, so the judge announced a mistrial and that was that.
-------------------------
* All of the duty; none of the deciding.
**The victim was still quite young at that time, and overwhelmed by the circumstances and the setting, and it was tough to watch from a few feet away for an afternoon and a morning.
posted by notyou at 8:47 AM on June 24, 2015 [1 favorite]
Also in the news, bite-mark "expert" Michael West isn't so sure anymore.
posted by rhizome at 9:52 AM on June 24, 2015 [3 favorites]
posted by rhizome at 9:52 AM on June 24, 2015 [3 favorites]
Surprise is not a reasonable reaction to imperfection.
posted by Flexagon at 10:56 AM on June 24, 2015
posted by Flexagon at 10:56 AM on June 24, 2015
Related: this is a really good, though depressing, Guardian piece on Kirk Odom who was recently released from 22 years in jail after a conviction based solely on a single strand of hair. (Released because he served his sentence, not because the evidence was found faulty - not yet anyway).
posted by Rumple at 12:50 PM on June 24, 2015 [2 favorites]
posted by Rumple at 12:50 PM on June 24, 2015 [2 favorites]
DNA matching might be problematic for conviction purposes, but DNA mismatches should still be exonerative, I'd hope.
posted by yesster at 2:30 PM on June 24, 2015 [2 favorites]
posted by yesster at 2:30 PM on June 24, 2015 [2 favorites]
Am I correct in reading this as the detective was doing the DNA testing and not a lab?
posted by LizBoBiz at 5:07 PM on June 24, 2015
posted by LizBoBiz at 5:07 PM on June 24, 2015
It was done by a lab, but the lab was given information that biased them. There is a fundamental conflict of interest when the people paying for the test prefer a specific result.
posted by idiopath at 8:37 PM on June 24, 2015
posted by idiopath at 8:37 PM on June 24, 2015
« Older Does it work on water? | Saga of the Sagas Newer »
This thread has been archived and is closed to new comments
posted by idiopath at 7:18 AM on June 24, 2015 [10 favorites]