Certificate course in Forensic Genetics & DNA
Database Technology, University of North Texas
Health Science Center at Fort Worth, Texas, USA
MSc Microbiology, University of the Philippines, Diliman

Areas of Current Research: Forensic DNA technology, human population genetics

Gayvelline C. Calacal specializes in the use of DNA technology for forensic applications. She is one of the senior DNA scientists at the University of the Philippines-Natural Sciences Research Institute-DNA Analysis Laboratory, (UPD-NSRI-DAL), mandated to establish the scientific framework of forensic DNA typing in the country with a goal of integrating DNA evidence as a standard investigative procedure in the justice system.

Gayvelline has made significant contribution in the development of forensic DNA typing technology in the country with her involvement in various research projects that include validation of sensitive and cost-efficient DNA typing procedures for analyzing biological samples for forensic casework applications and evaluation of evidence management system, collection, transport and storage of evidentiary materials [1-3]. She puts into life her advocacies to help others through her extensive research activities on human identification, provide forensic DNA evidence in aid of justice and bringing science at the service of the society.

She has likewise contributed to the generation and expansion of the Philippine reference population genetic databases. These databases are used in the statistical analysis of matching DNA evidence between the evidentiary samples and reference samples collected from the individual or the person’s nearest kin. Early research published by UPD-NSRI-DAL made use of eight autosomal [4-6] and seven Y-chromosomal DNA STR markers [7-8]. Development of multiplex assays markedly increased the amount of genetic information that could be obtained per sample at any given time. Since then, the Philippine population database has expanded to include more samples from different population groups and the scope of the Philippine genetic databases was increased using autosomal STR’s [9-11] and other different DNA typing technologies. The availability of autosomal and lineage DNA markers enabled the laboratory to conduct different types of genetic tests [12] based on the availability of DNA samples and the nature of the investigation. Currently, the UPD-NSRI-DAL team is working towards the inclusion of additional samples from regional and different ethno-linguistic groups in the Philippine population database, for it to be a better tool for statistical evaluation of forensic DNA evidence. Moreover, the information that can be derived from this comprehensive study can offer a number of important insights into the genetic variation of Philippine groups, the Filipino genetic heritage and can provide a better understanding of the models of human settlement in the Asian region [13-15].

Gayvelline is an active agent in the promotion of DNA forensics through information dissemination in lectures and her participation in training programs for the academe, students, law enforcement officers, judges, legal and medical professionals, scientists and the general public. Her works contributed to the general public’s trust in the capability of the UPD-NSRI-DAL in handling different types of cases involving DNA testing.
In addition, Gayvelline has performed DNA tests on different forensic casework samples [12] to aid in the resolution of civil and criminal disputes involving questioned paternity/maternity [16-20], determining sources of dubious tissue specimen, identity fraud, suspected child switching, sexual assault [21], suspected child trafficking cases, post-conviction DNA testing [22] and identification of human remains as part of a criminal or human rights investigation. She has extended her assistance and expertise in disaster victim identification efforts [23-24]. In addition, Gayvelline appears before Philippine courts as an expert witness to testify on DNA typing results in forensic cases that were handled by the UPD-NSRI-DAL. She has assisted the courts by providing her expert opinion regarding the significance of DNA testing in the resolution of these cases.


  1. Calacal GC, Apaga DLTA, Salvador JM, Jimenez JAD, Lagat LJ, Villacorta RPF, Lim MCF, Fortun RdR, Datar FA and De Ungria MCA.2015. Comparing different post-mortem human samples as DNA sources for downstream genotyping and identification. Forensic Science International: Genetics 19:212–220.
  2. Calacal GC and De Ungria MCA. 2005. Fungal DNA challenge in human STR typing of bone samples. Journal of Forensic Science. 50(6):1394-1401.
  3. Perdigon HB, Calacal GC, Co Seng KL, Halos S and De Ungria MCA. 2004. Evaluation and in-house validation of five DNA extraction methods for PCR-based STR analysis of bloodstained denims. Science Diliman. 16(1):37-48.
  4. De Ungria MCA, Ferrer AMF, Tabbada KA, Tan MMM, Delfin FC, Calacal GC and Halos SC. 2002. The Philippine Genetic Database of Short Tandem Repeats (STR) in DNA-based Paternity Testing. Philippine Journal of Science.131 (1):1-8.
  5. De Ungria MCA, Tabbada KA, Delfin FC, Magno MMF, Calacal GC, Frani AM and Halos SC. 2002. Resolving paternity disputes using a Philippine genetic database. Science Diliman. 14(1):8-16.
  6. Tabbada KA, Magno MMF, Delfin FC, Calacal GC, Tan M, Chu-Ferreon JY, Halos SC and De Ungria MCA. 2002. Allele frequencies of eight Short Tandem Repeat Loci in three Visayas Regional Populations of the Philippines. Journal of Forensic Science. 47(6):1-2.
  7. Lessig R, Willuweit S, Krawczak M, Wu FC, Pu CE, Kim W, Henke L, Henke J,Miranda J, Hidding M, Benecke M, Schmitt C, Magno M, Calacal GC, Delfin FC, De Ungria MCA, Elias S, Augustin C, Tun Z, Honda K, Kayser M, Gusmao L, Amorim A, Alves C, Hou Y, Keyser C, Ludes B, Klintschar M, Immel UD, Reichenpfader B, Zaharova B, Roewer L. 2003. Asian online Y-STR Haplotype Reference Database. Legal Medicine (Tokyo). Mar; 5 Suppl 1:S160-3.
  8. Tan MM, Calacal GC, Delfin FC, Roewer L. and De Ungria MCA. 2003. Allele Frequency Distribution of the Y-chromosomal STR haplotype of Filipinos in the NCR for Forensic Applications. Philippine Journal of Science. 132(2):95-101.
  9. Salvador JM, Calacal GC, Villamor LP and De Ungria MCA. 2007. Allele frequencies for two pentanucleotide STR loci Penta D and Penta E in a Philippine population. Legal Medicine. 9(5):282-283.
  10. Maiquilla SMB, Salvador JM, Calacal GC, Delfin FC, Tabbada KA, Perdigon HB, Sagum MS, Dalet MRM, De Ungria MCA. 2011. Expansion of the Philippine autosomal short tandem repeat population database for DNA-based paternity testing. Philippine Journal of Science. 140: 1-6.
  11. Rodriguez JJRB, Salvador JM, Calacal GC, Laude RP and De Ungria MCA. 2015. Allele frequencies of 23 autosomal short tandem repeat loci in the Philippine population. Legal Medicine.17:295-297.
  12. De Ungria MCA, Calacal GC, Delfin FC, Tabbada KA, Salvador JM, Sagum MS, Dalet MRM, Franco SAEL, Maiquilla SMB, Perdigon HB, Villamor LP and Halos SC. 2008. Forensic DNA testing by the UP-NSRI DNA Analysis Laboratory. Acta Medica Philippina. 42(2):34-38.
  13. Delfin FCD, Ko AMS, Mingkun L, Gunnarsdottir ED, Tabbada KA, Salvador JM, Calacal GC, Sagum MS, Datar FA, Padilla SG, De Ungria MCA and Stoneking M. 2014. Complete mtDNA genomes of Filipino ethnolinguistic groups: a melting pot of recent and ancient lineages in the Asia-Pacific region. European Journal of Human Genetics. 94:426-436. 22: 228-237
  14. Delfin FC, Salvador JM, Calacal GC, Perdigon HB, Tabbada KA, Villamor LP, Halos SC, Gunnarsdottir E, Myles S, Hughes DA, Xu S, Jin L, Lao O, Kayser M, Hurles ME, Stoneking M and De Ungria MCA. 2010. The Y-chromosome landscape in the Philippines: extensive heterogeneity and varying genetic affinities of Negrito and non-Negrito groups. European Journal of Human Genetics. 19: 224–230.
  15. The HUGO Pan Asia SNP Consortium. 2009. Mapping human genetic diversity in Asia. SCIENCE. 326 (5959):1541-1545.
  16. Calacal GC, Salvador JM, Franco SAEL, Tabbada KA, Sagum MS, Maiquilla SMB and De Ungria MCA. 2008. Case Report: DNA tests for maternity determination. Acta Medica Philippina. 42(2):39-42.
  17. Dalet MRM, Salvador JM, Calacal GC, Sagum MS and De Ungria MCA. 2012. DNA test leads reunion of child with real mother. Forensic Asia. 4:27-28.
  18. De Ungria MCA, Frani AM, Magno MMF, Tabbada KA, Calacal GC, Delfin FC and Halos SC. 2002. Evaluating DNA tests of motherless cases using a Philippine genetic database. Transfusion. 42(7):954-958.
  19. De Ungria MCA, Magno MMF, Tabbada KA, Calacal GC, Delfin FC, Frani AM and Halos SC. 2002. Interpreting DNA evidence in disputed parentage cases. The IBP Newsletter. 30-31.
  20. De Ungria MCA, Magno MMF, Calacal GC, Delfin FC, Tabbada KA, Frani AM and Halos SC. 2001. DNA evidence in Philippine courts: a case report. Philippine Law Gazette. 13(3):46-49.
  21. Maiquilla SMB, Salvador JM, Calacal GC, Sagum MS, Dalet MRM, Delfin FC, Tabbada KA, Franco, SAEL, Perdigon HB, Madrid BJ, Tan MP, and De Ungria MCA. 2011. Y-STR DNA Analysis of 154 female child sexual assault cases in the Philippines. International Journal of Legal Medicine.125:817-824.
  22. De Ungria MCA, Sagum MS, Calacal GC, Delfin FC, Tabbada KA, Dalet MRM, Te TO, JI Diokno, MSI Diokno and CA Asplen. 2008. Forensic DNA evidence and the death penalty in the Philippines. Forensic Science International: Genetics. 2(4)329-332.
  23. Calacal GC, Delfin FC, Tan MM, Roewer L, Magtanong DL, Lara M, Fortun R dR and De Ungria MCA. 2005. Identification of exhumed remains of fire tragedy victims using conventional methods and autosomal/Y-Chromosomal Short Tandem Repeat DNA profiling. American Journal of Forensic Pathology and Medicine. 26(3):285-291.
  24. Calacal GC, De Ungria MCA, Delfin FC, Lara M, Magtanong DL and Fortun RdR. 2003. Identification of Two Fire Victims by Comparative Nuclear DNA Typing of Skeletal Remains and Stored Umbilical Tissues. American Journal of Forensic Pathology and Medicine. 24(2):148-152.