Identification of exhumed remains of fire tragedy victims using conventional methods and autosomal/Y-chromosomal short tandem repeat DNA profiling

In a fire tragedy in Manila in December 1998, one of the worst tragic incidents which resulted in the reported death of 23 children, identity could not be established initially resulting in the burial of still unidentified bodies. Underscoring the importance of identifying each of the human remains, the bodies were exhumed 3 months after the tragedy. We describe here our work, which was the first national case handled by local laboratories wherein conventional and molecular-based techniques were successfully applied in forensic identification. The study reports analysis of DNA obtained from skeletal remains exposed to conditions of burning, burial, and exhumation. DNA typing methods using autosomal and Y-chromosomal short tandem repeat (Y-STR) markers reinforced postmortem examinations using conventional identification techniques. The strategy resulted in the identification of 18 out of the 21 human remains analyzed, overcoming challenges encountered due to the absence of established procedures for the recovery of mass disaster remains. There was incomplete antemortem information to match the postmortem data obtained from the remains of 3 female child victims. Two victims were readily identified due to the availability of antemortem tissues. In the absence of this biologic material, parentage testing was performed using reference blood samples collected from parents and relatives. Data on patrilineal lineage based on common Y-STR haplotypes augmented autosomal DNA typing, particularly in deficiency cases.     

Forensic DNA evidence and the death penalty in the Philippines

The death penalty remains a contentious issue even though it has been abolished in countries such as Australia, New Zealand, Canada, European Union member nations and some Asian countries such as Cambodia, East Timor and Nepal. Many argue that the irrevocability of the death penalty, in the face of potential erroneous convictions, can never justify its imposition. The Philippines, the first Asian country that abolished the death penalty in 1987, held the record for the most number of mandatory death offenses (30 offenses) and death eligible offenses (22 offenses) after it was re-imposed in 1994. Majority of death penalty convictions were decided based on testimonial evidence. While such cases undergo automatic review by the Supreme Court, the appellate process in the Philippines is not structured to accept post-conviction evidence, including DNA evidence.Because of the compelling nature of post-conviction DNA evidence in overturning death penalty convictions in the United States, different groups advocated its use in the Philippines. In one such case, People v Reynaldo de Villa, the defendant was charged with raping his 13-year-old niece that supposedly led to birth of a female child, a situation commonly known as ‘criminal paternity’. This paper reports the results of the first post-conviction DNA test using 16 Short Tandem Repeat (STR) DNA markers in a criminal paternity case (People v Reynaldo de Villa) and discusses the implications of these results in the Philippine criminal justice system.     

Identification of two fire victims by comparative nuclear DNA typing of skeletal remains and stored umbilical tissues

We describe here our collaborative efforts in identifying 2 fatalities of a fire disaster by using a variety of identification techniques. Postmortem findings in both cases were reinforced using Short Tandem Repeat (STR) DNA technology to establish with a high degree of certainty the identities of 2 child victims. STR markers used in the present study include HUMAMEL, HUMCSFIPO, HUMTHO1, HUMvWA, HUMFES/FPS, HUMF13A01, HUMFOLP23, D8S3O6, HUMFGA, and HUMTPOX. Unambiguous identification was made possible through matching DNA profiles generated from skeletal remains with those from umbilical tissues. These tissues were kept by their mothers in accordance with a Philippine tradition and were submitted for DNA analysis. Of the DNA profiles generated from exhumed bone samples of 21 child victims, comparison with the genetic profiles of children A and B obtained from umbilical tissues showed consistent DNA matches with remains 1756 and 1758, respectively.     

Fungal DNA challenge in human STR typing of bone samples

The present study focuses on possible cross-reaction of fungal DNA with human STR primers that may affect subsequent forensic DNA analysis of forensic samples. Specificity of human STR markers namely HUMAMEL, HUMCSF1PO, D8S306, HUMTH01, HUMvWA, HUMFES/FPS, HUMF13A01, HUMDHFRP2, HUMFGA and HUMTPOX was tested using DNA of 24 different filamentous fungal isolates obtained from exhumed bone samples. The specificity of these ten STR markers for human DNA was demonstrated. Presence of non-human DNA in five bone samples analyzed did not alter scoring of detected alleles. Notably, amplification was inhibited in the presence of a high proportion of fungal DNA compared to human DNA (1000 ng: 1 ng) in DNA mixture experiments. The results of the present study underscore the importance of carefully analyzing the presence of non-human biological contaminants that may affect DNA typing of environmentally challenged forensic samples to avoid spurious data interpretation.     

HS/GC/ECD分析生物检材样品中的氰化物

目的 建立生物样品中氰化物的衍生化定性定量分析方法。方法 用氯胺T衍生化,HS/GC/ECD分析衍生物CICN。结果 在1ml血中,添加0.2μg氰化钾,回收率为84.6％,RSD为6.39％;在1g肝中添加0.5μg氰化钾,回收率为67.3％,RSD为5.05％;血中检出限为5ng/ml。结论 所建方法能定性定量分析生物样品中的氰化物。