It’s in the genes (1)

published 18 Aug 2008, MST

Not too many are aware that the technology for DNA typing is already available in the Philippines. DNA, of course, stands for deoxyribonucleic acid, the genetic blueprint that makes each person, except identical twins, unique. DNA typing is a process of extracting and analyzing the genetic information from a biological sample—such as blood (most common), saliva, semen, hair, tissues and bones.

Maria Corazon de Ungria, Ph.D. heads the University of the Philippines-National Science Research Institute DNA Analysis Laboratory. Established in 1996, the laboratory is one of the four institutions (the others are the National Bureau of Investigation, the National Police and St. Luke’s Medical Center) that make use of the short-tandem repeat (STR) method for genetic analysis. She says that advances in the field have made breakthroughs in civil and criminal disputes possible. Philippine law has made provisions for the admissibility of DNA evidence for the determination of paternity as well as for the establishment of guilt in sexual abuse cases. Genetic information can also identify of casualties of mass disasters like fires or sunken vessels.

In 2001, the Supreme Court, in the case of Tijing and Tijing vs. Court of Appeals and Diamante, ruled in favor of a couple whose child was taken by a woman, brought to her hometown and passed off as her own son. The court based its judgment on the conventional methods of determining paternity—for example, the admission of the respondent that she was no longer able to bear children, the incapacity of her common-law husband to sire children, the striking facial resemblance of the child with the petitioner, and the irregular way in which the child’s birth certificate was filed. As a final note, the court also suggested the option of using DNA analysis for a scientific basis for determining the child’s parentage.

Certainly, much has happened since this “suggestion.”

In the landmark case of the People vs. Vallejo (2002), the Supreme Court convicted a man for raping and later killing a 9-year-old child. This was the first time the court admitted DNA information as evidence in court. The DNA obtained from vaginal swabs taken from the child was found to be consistent with that of the accused.

The decision laid down the essential standards for the admissibility of DNA information in court. Among those to be considered: The manner of collecting and handling samples, the possibility of contamination, the procedure followed in the analysis, observation of the proper standards and procedures in the conduct of the test, as well as the accreditation of the DNA laboratory conducting the test or, in the absence of accreditation, the qualification of the analyst performing the typing.

The UP laboratory, with funding from the UP Center for Integrative Studies, is currently working on formulating a national strategy for the local accreditation of forensic DNA laboratories in the Philippines to address the issue of accreditation.

In the meantime, only the best and most accomplished in the field, such as De Ungria herself, lend their expertise to the typing process to satisfy this last condition of the Supreme Court. The results of the test are only ready after at least 14 working days from the date of the sampling. More complex cases, of course, require more time. De Ungria says the results take longer to release because the laboratory uses a three-level review process. A probability of 99.9 percent or greater is considered presumptive proof of parentage.

In October 2007, the high court released its Rules on DNA Evidence, honing the standards it had already set in the Vallejo case. It enumerated requirements in the determination of the reliability of the testing method and the testing results. At around the same time, the court remanded the case of the People vs. Umanito to the trial court for reception of DNA evidence. These are, of course, questions of fact, something which the Supreme Court is not a trier of.

De Ungria says that after the rules had been promulgated, the laboratory saw an increase in its casework. These cases in paternity testing and human identification are usually used in civil (recognition, support, inheritance) or criminal (rape) disputes.

Then again, working on actual cases is only part of the institute’s mandate. Scientists at the laboratory, in collaboration with specialists from related fields, also conduct research and publish them in journals that make up literature—and spell authority—on the subject.

For example, De Ungria’s work, DNA Evidence in Paternity Cases, was printed in the Philippine Law Journal in December 2005. In her paper, De Ungria emphasized that DNA provided scientific evidence that was more conclusive than testimonies, which could be affected by numerous external factors.

Ascendancy over the victim, for instance, is a factor that may affect testimonies. Imagine a child who had been sexually abused. It is naturally difficult for her (or him) to narrate her experiences in court. Furthermore, it might be traumatic for her to actually point to her assailant if that aggressor has authority over her—a father, older brother, grandfather, or even a respected neighbor or teacher.

Y-STR Analysis for Detection and Confirmation of Child Sexual Abuse, conducted by Frederick Delfin, Bernadette Madrid, Merle Tan and De Ungria, was published in the International Journal of Legal Medicine in 2004. The study sought to establish that rape could be proven, using DNA evidence, without having to subject the child to the traumatic experience of recounting their tales or actually pointing to their aggressors. Samples from 26 abused children (25 female and one male) between the ages of 2 and 17 were collected between six and 72 hours after the incident allegedly took place. The scientists employed a Y-chromosome STR analysis (as opposed to another method, the autosomal STR analysis) and obtained a 92.33 percent “success” rate (24 of the 26 tested positive for rape). Assuming that the victims have had no sexual history prior to the incident, a contaminated DNA proves only that some other person’s blueprint found its way into the victim’s body. Such an objective finding would be impossible to overturn by the testimonies of a traumatized victim or denials of an accused.

More on the applications of DNA typing next week.

* * *

In last Monday’s column (Mental training in sports), I made reference to the Southeast Asian International Table Tennis Championship. It should have read the Southeast Asian Junior Table Tennis Championships. My apologies.