Bulletin: Major development: "Grits for Breakfast" breaks yet another major story ignored by the mainstream media: "A reluctant scoop: Changing intepretations of DNA mixtures vex legal system."..."The most recent such development: improvements in DNA science and interpretation techniques have caused practitioners to change how they calculate probabilities when it comes to accusing a defendant based on DNA mixtures. In the most extreme instance, the new method reduced a one in a billion probability that evidence matched a particular suspect to around one in 50, the Texas Forensic Science Commission's Lynn Garcia told the Texas Criminal Justice Integrity Unit (TCJIU) on Wednesday.".....Grits comments: "So many other questions are raised, it boggles the mind to consider. No one knows how many cases are involved, but the fear is it's a lot: Many more than in the FSC's hair microscopy review, which is itself expected to take years."

Countdown to Wrongful Conviction Day:  Friday, October 2,  2105; 27 days. For information: http://www.aidwyc.org/wcd-2015/

"DNA has often been referred to as the gold standard of forensic evidence. And when comparing a single sample to a suspect, that's true. When DNA evidence includes mixtures of DNA from multiple sources, however, the scientific community is still figuring things out. And it takes years for new knowledge to pass down from the highest-end basic research to the work tables of practicing DNA analysts at front-line crime labs. The most recent such development: improvements in DNA science and interpretation techniques have caused practitioners to change how they calculate probabilities when it comes to accusing a defendant based on DNA mixtures. In the most extreme instance, the new method reduced a one in a billion probability that evidence matched a particular suspect to around one in 50, the Texas Forensic Science Commission's Lynn Garcia told the Texas Criminal Justice Integrity Unit (TCJIU) on Wednesday. The issue was first publicly revealed in Texas and, to their credit, the courts and relevant agencies have been quick to confront the challenge, even if nobody quite knows yet what to do. Grits has put off writing about this topic for a while, mainly because I hoped the MSM (main stream media HL)  would pick up the story  - it's a big one, with national and even international implications - and thus do me the favor of not having to write up a complicated issue (this blog is a hobby for me, after all). But it doesn't appear anyone else will cover it, so it falls to your correspondent to break the news.........This all began when the FBI identified a handful of errors in its CODIS DNA database (51 problems out of tens of thousand of entries) and issued a public notice saying that the change in any probabilities affected would be insignificant. Garcia said the largest discrepancy estimated from the data-entry errors would have reduced a likelihood of one in 260 billion that it belonged to another person to one in 225 billion. With seven billion people on the planet, that looked like a yawner. But some Texas prosecutors asked for their probabilities to be recalculated, anyway, and when they came back, they were affected to a far greater extent than had previously been portrayed. The most radical difference involved the case mentioned above where a one-in-a-billion probability was lowered to around one-in-fifty, said Garcia. At that, prosecutors and the FSC perked up and took notice. It turned out, the difference stemmed not from the data entry errors but because - in response to all that complex and sciency stuff that I'm not going to attempt to explain here - the FBI had changed its methodology in calculating probabilities for mixtures and moved to a new method which they considered more accurate. According to the FSC notice, "Changes in mixture interpretation have occurred primarily over the last 5-10 years and were prompted by several factors, including but not limited to mixture interpretation guidance issued in 2010 by the [national] Scientific Working Group on DNA analysis" (see here). When they changed methodologies, though, scientists didn't think to notify prosecutors, much less the defense bar. Apparently, nobody wondered, "What happens when you apply the new method to old cases?," much less, "What if a defendant included by the old method is excluded or undetermined under the new one"? Those are the questions the wider legal community is struggling with now, at the moment in Texas but very soon across the country and everywhere on the planet where DNA evidence is used in courts. "So many other questions are raised, it boggles the mind to consider. No one knows how many cases are involved, but the fear is it's a lot: Many more than in the FSC's hair microscopy review, which is itself expected to take years."
http://gritsforbreakfast.blogspot.ca/2015/09/a-reluctant-scoop-changing.html