This month, the Supreme Court issued the Rule on DNA Evidence, through A.M. No. 06-11-5-SC, 2 October 2007. The full text of the Rule on DNA Evidence is at the Philippine e-Legal Forum. The use of DNA in cases gained popularity in recent years. In 2005, the Supreme Court required certain trial court judges to attend a symposium on the use of DNA analysis in court.
It is used not only in criminal cases, but also in paternity disputes, and the discussions in these cases are instructive as to the history and nature of this kind of evidence. For instance, in a case involving the identity of a missing son (Tijing vs. Tijing), the Supreme Court noted that:
“Parentage will still be resolved using conventional methods unless we adopt the modern and scientific ways available. Fortunately, we have now the facility and expertise in using DNA test for identification and parentage testing. The University of the Philippines Natural Science Research Institute (UP-NSRI) DNA Analysis Laboratory has now the capability to conduct DNA typing using short tandem repeat (STR) analysis. The analysis is based on the fact that the DNA of a child/person has two (2) copies, one copy from the mother and the other from the father. The DNA from the mother, the alleged father and child are analyzed to establish parentage. Of course, being a novel scientific technique, the use of DNA test as evidence is still open to challenge. Eventually, as the appropriate case comes, courts should not hesitate to rule on the admissibility of DNA evidence. For it was said, that courts should apply the results of science when competently obtained in aid of situations presented, since to reject said result is to deny progress. Though it is not necessary in this case to resort to DNA testing, in future it would be useful to all concerned in the prompt resolution of parentage and identity issues.
In a criminal case for Rape with Homicide (People vs. Yatar), the Supreme Court affirmed the conviction of the accused. Among the discussion relates to DNA:
Significantly, subsequent testing showed that the Deoxyribonucleic acid (DNA) of the sperm specimen from the vagina of the victim was identical the semen to be that of appellant’s gene type.
DNA is a molecule that encodes the genetic information in all living organisms. A person’s DNA is the same in each cell and it does not change throughout a person’s lifetime; the DNA in a person?s blood is the same as the DNA found in his saliva, sweat, bone, the root and shaft of hair, earwax, mucus, urine, skin tissue, and vaginal and rectal cells. Most importantly, because of polymorphisms in human genetic structure, no two individuals have the same DNA, with the notable exception of identical twins.
DNA print or identification technology has been advanced as a uniquely effective means to link a suspect to a crime, or to exonerate a wrongly accused suspect, where biological evidence has been left. For purposes of criminal investigation, DNA identification is a fertile source of both inculpatory and exculpatory evidence. It can assist immensely in effecting a more accurate account of the crime committed, efficiently facilitating the conviction of the guilty, securing the acquittal of the innocent, and ensuring the proper administration of justice in every case.
DNA evidence collected from a crime scene can link a suspect to a crime or eliminate one from suspicion in the same principle as fingerprints are used. Incidents involving sexual assault would leave biological evidence such as hair, skin tissue, semen, blood, or saliva which can be left on the victim?s body or at the crime scene. Hair and fiber from clothing, carpets, bedding, or furniture could also be transferred to the victim’s body during the assault. Forensic DNA evidence is helpful in proving that there was physical contact between an assailant and a victim. If properly collected from the victim, crime scene or assailant, DNA can be compared with known samples to place the suspect at the scene of the crime.
The U.P. National Science Research Institute (NSRI), which conducted the DNA tests in this case, used the Polymerase chain reaction (PCR) amplification method by Short Tandem Repeat (STR) analysis. With PCR testing, tiny amounts of a specific DNA sequence can be copied exponentially within hours. Thus, getting sufficient DNA for analysis has become much easier since it became possible to reliably amplify small samples using the PCR method.
In assessing the probative value of DNA evidence, courts should consider, inter alia, the following factors: how the samples were collected, how they were handled, the possibility of contamination of the samples, the procedure followed in analyzing the samples, whether the proper standards and procedures were followed in conducting the tests, and the qualification of the analyst who conducted the tests.
In the case at bar, Dr. Maria Corazon Abogado de Ungria was duly qualified by the prosecution as an expert witness on DNA print or identification techniques. Based on Dr. de Ungria’s testimony, it was determined that the gene type and DNA profile of appellant are identical to that of the extracts subject of examination. The blood sample taken from the appellant showed that he was of the following gene types: vWA 15/19, TH01 7/8, DHFRP2 9/10 and CSF1PO 10/11, which are identical with semen taken from the victim?s vaginal canal. Verily, a DNA match exists between the semen found in the victim and the blood sample given by the appellant in open court during the course of the trial.
Admittedly, we are just beginning to integrate these advances in science and technology in the Philippine criminal justice system, so we must be cautious as we traverse these relatively uncharted waters. Fortunately, we can benefit from the wealth of persuasive jurisprudence that has developed in other jurisdictions. Specifically, the prevailing doctrine in the U.S. has proven instructive.
In Daubert v. Merrell Dow, it was ruled that pertinent evidence based on scientifically valid principles could be used as long as it was relevant and reliable. Judges, under Daubert, were allowed greater discretion over which testimony they would allow at trial, including the introduction of new kinds of scientific techniques. DNA typing is one such novel procedure.