The August ABA Journal landed in my mailbox. Usually, I ask reporters to check the wording with me before quoting me, but I neglected to do so some weeks ago, when Mark Walsh asked me about DNA databases in the aftermath of the Supreme Court’s opinion in Maryland v. King. Mr. Walsh’s article quotes me as follows: “Is the point of arrest the sensible place to draw the line? I can imagine a system in which you take a sample from everyone. Newborns already have a heel prick taken for certain genetic testing. At the same time you could take a DNA sample. Not that you expect a newborn to commit a crime, but 20 years later the sample is there in the database.”
Oops! I said that? I meant to say this: “Is the point of arrest the sensible place to draw the line? I can imagine a system in which you take a sample from everyone. Newborns already have a heel prick taken for certain genetic testing. Along with the genetic tests of the DNA, you could obtain a DNA profile. Not that you expect a newborn to commit a crime, but 20 years later the profile is there in the database.” The critical difference: “profile,” not “sample.”
For more on creating a population-wide database with police never touching your DNA, see this FSSL blog posting.
When you get results that might be explained by (1) degradation and contamination or (2) Sasquatch, it’s Sasquatch. After all, forensic scientists know how to deal with contamination, don’t they? For more, see the FSSL blog posting or the full Ars Technica analysis.
An op-ed article in yesterday’s New York Times speaks of DNA database hits as “high risk.” That police, prosecutors, defense lawyers, and juries should not accept every hit as conclusive proof of guilt is quite true. To prove the point, the article calls attention to a false arrest in the ongoing California case of the murder of millionaire investor Raveesh Kumra — a matter that made the news last month. Although the facts of the case are atypical, it is a warning to overly credulous police and prosecutors.
The article, by Hastings Law Professor Osagie K. Obasogie, also rehashes two dated — and previously refuted (or so I think) incidents — that are supposed to show that DNA databases are producing lots of false hits. Some of the factual and statistical errors in the article are identified in the Forensic Science, Statistics, and the Law Blog (http://for-sci-law-now.blogspot.com/2013/07/good-point-bad-math-dna-database.html).
Thomas Kriesel wants his blood back. The federal government forced him to give a sample for the FBI’s national DNA databank while he was on probation following his imprisonment for conspiring to possess methamphetamine with the intent to distribute it. After completing his sentence, Kriesel sued the government. He demanded that it remove his identifying profile from the federal database and return his blood sample.
The district court held that he was not entitled to expungement of the profile. On appeal, he dropped that part of his claim, but continued to argue for the return of the blood sample. Over a clamorous dissent, the Ninth Circuit upheld the indefinite retention of the sample. Comments on the opinions are on the FSSL blog.
The title of a New Scientist news report — “Software Says Amanda Knox’s DNA Wasn’t at Crime Scene” — suggests that a new study has excluded Knox as a killer of Meredith Kercher. Not so fast, says the Professor David Balding, the author of the study.
Balding, a statistical geneticist at University College London, has made important contributions to the statistical evaluation of forensic DNA profiles. Now he is developing an open-source program to make inferences about the contributors to low-template DNA samples — samples that have too few copies of DNA fragments to amplify reliably.
An article in the Proceedings of the National Academy of Sciences (USA) describes the program and applies it to an electropherogram the police obtained from one sample in the Knox-Sollecito case. Seeking to clarify the New Scientist report, Balding describes this finding on his website … [continued on FSSL]