The double helix in court: DNA as catalyst for change

The basic DNA properties of inheritability, chemical stability, identity of biological samples originating from one person and the uniqueness of the totality of an individual’s DNA profile make this chemical the most effective tool for human identification. In the Philippines where testimonies comprise the most common and at times, the only evidence presented in court, the development of forensic DNA testing to assist in criminal investigations and resolve civil disputes provides a novel tool to a justice system that at times has been seen as slow, biased and inefficient. With the mandate to pioneer the development of forensic DNA technology in the Philippines, the DNA Analysis Laboratory of the Natural Sciences Research Institute (UP-NSRI DAL) was established in May 1996. The contribution of rigorous academic research, committed forensic scientists and supportive partners/collaborators in laying the foundation for the technology in the country is evident in the past 18 years of the laboratory’s existence (www.dnaforensic.org).

In addition to conducting basic research, the laboratory has been actively involved in a number of landmark cases which now form part of Philippine jurisprudence. In 2001, the Supreme Court gave judicial notice on the capability of the UP-NSRI DAL to resolve parentage issues in the case of Edgardo and Bienvenida Tijing vs Court of Appeals and Angelita Diamante (G.R. No. 125901). In this case, two mothers were claiming to be the biological mother of a child. Although the Supreme Court finally decided that Bienvenida Tijing was the mother of the child based on evidence already presented, it also cited the possibility of conducting DNA tests at the UP-NSRI DAL if Angelita Diamante continued to pursue her claim. The decision reflected the evolving view of the judiciary on the value and utility of DNA evidence in resolving disputed parentage cases. In 2005, the Supreme Court, in its decision on the issue of paternity in Rosendo Herrera vs Rosendo Alba (G.R. No. 148220), went a step further by defining the minimum value of the Probability of Paternity needed for the court to presume that the alleged father is the biological father of a child. Once DNA test results establishing paternity are submitted to the court, the burden of proof shifts from the child and his/her mother to the alleged father to present evidence, such as his own medical records, to dispute the DNA results. This is a significant change in the mindset of the family courts that previously would take years to evaluate a woman’s paternity claim. Moreover, this minimum Probability of Paternity value equal to 99.9 percent may only be obtained if DNA testing is conducted, thus highlighting the effectiveness of DNA testing over blood typing, a method used during the pre-DNA years.

In 2004, the Supreme Court ruled in People vs Joel Yatar (G.R. No. 150224), that the right against self-incrimination invoked by persons who refuse to provide biological samples for DNA testing, applies only to testimonial evidence, but not physical evidence such as DNA. The UP-NSRI DAL conducted the DNA tests on the vaginal smears of the victim in this rape-homicide case. In the process of DNA testing, the laboratory detected non-victim DNA in the smear taken from the victim which later on was found to be consistent with that of the accused. Hence the judge found Joel Yatar guilty of raping and killing the victim and sentenced him to death. During the Supreme Court review of this case, the defense attempted to have the DNA evidence excluded by invoking Joel Yatar’s constitutional right against self-incrimination. The Supreme Court, however, found no merit in this argument and instead recognized the admissibility of DNA evidence, thereby preventing the party from invoking the right against self-incrimination to delay the conduct of DNA tests in this and all other cases.

And finally in October 2007, the Supreme Court promulgated the Rule on DNA Evidence which laid the foundation for the use of DNA evidence in Philippine courts. The Rule does not only provide guidance to trial court judges regarding the admissibility, relevance and probative value of DNA evidence, but it also opens the possibility of post-conviction DNA testing to reopen cases which have long been final and executory to determine whether an accused may have been wrongfully convicted. The UP-NSRI DAL assisted in the drafting of the Rule by providing technical support, drawing from the expertise of its personnel as well as the lessons from the many cases that the laboratory had handled through the years. Indeed, the DNA helix, although not visible to the naked eye, has promoted significant changes in the manner by which the justice system appreciated physical evidence in courts, and altering the dynamics in Philippine courts.

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This lecture was delivered at the Research Colloquium held during the 30th anniversary of the Natural Sciences Research Institute, University of the Philippines Diliman last March 25-27. The author is the current head of the DNA Analysis Laboratory, one of the in-house research and service laboratories of the NSRI (www.nsri.upd.edu.ph). She has appeared as expert witness in cases involving disputed parentage issues and in relation to criminal cases. She provided her technical assistance during the formulation of the Rule on DNA Evidence and her opinion on different bills regarding forensic DNA technology. The UP-NSRI DNA Laboratory continues to offer its parentage testing and DNA profiling expertise as part of its commitment to serve the community. The laboratory may be contacted at 632 925-2965, 639189136284 and [email protected].