In an October 3 announcement, the National Institute of Standards and Technology (NIST) gave notice that it will undertake “a study to assess the reliability of forensic methods for analyzing DNA evidence that, if misapplied, could lead to innocent people being convicted.” The study will focus on DNA mixtures involving three or more people and so-called “touch samples” involving very small quantities of DNA. The goal is to measure the reliability of DNA profiling methods in these circumstances.
According to the NIST, the process of interpreting DNA touch and mixtures containing three-or-more people “can be subjective” and there are “currently no clearly defined standards for doing so.” Thus, different analysts may come to different conclusions interpreting the same evidence. Some laboratories will not do anything with such samples, while other laboratories may go too far in their interpretations. Moreover, although scientific studies support the reliability of DNA testing involving samples from one or two people, it can be difficult to “tease apart the different profiles” when the sample contains three or more people, according to NIST.