Genetic genealogy and ancestry: Exploring what is written in one’s DNA

Genealogy is the study of families and tracing of their lineages and history. Studying one’s genealogy may be motivated by many reasons such as 1) in determining a family’s place in national history; 2) in preserving the family’s past for future generations; and 3) in contributing to the “storytelling” of the events that had passed so many years before. Traditional genealogical research involves the gathering and study of documents, including worn-out government records and oral narratives in order to determine the relationship of one individual to a family.

More recently, genealogical DNA tests gained popularity because of the relative ease in determining relationships, e.g. paternity and maternity, between an “alleged” parent and a child. The availability of lineage markers which further extends the scope of the type of familial relationship that may be tested with great accuracy through several generations, had significantly increased the use of these tests. The use of Y-DNA and mitochondrial DNA (mtDNA) to determine paternal or maternal lineages, respectively, has opened possibilities to traditional genealogists and historians. “Genetic genealogy” may now serve to supplement the traditional genealogical research. In the Philippines where many government records are difficult to find, contain inaccuracies or are no longer available, the availability of genealogical DNA tests provides an alternative option for individuals, including historians, in tracing family histories.

In addition to lineage markers on the Y and mitochondrial DNA, single nucleotide polymorphism (SNP) markers may be used to characterize the genetic ancestry of persons. The results of genome scans may be subjected to Principal Component Analysis (PCA) in order to identify a panel of Ancestry Informative Markers (AIMs) that would distinguish a family or a population, from other samples who are not members of the group. In doing this, a better understanding of a family or a population’s genetic association or differentiation, with others, may be obtained.

The development of whole genome association studies (WGA) has accelerated the search for inheritable genetic variations that may be associated with complex diseases. The level of genetic variation of specific SNP markers in populations driven largely by natural selection may lead to false positive associations. In order to reduce the possibility of false positive associations, genetic ancestry differences between cases and controls in a clinical study, for example, must be accounted for. To evaluate whether population stratification does exist, AIMs must be identified and characterized within populations. The panel of AIMs may vary from one population to the next, hence a panel of AIMs that had been identified for European populations, may not be used in other populations such as the Philippines. Even within a population that may have sub-population stratification, AIMs must be identified to properly evaluate the results of any study involving this population.

In the Philippines, we propose to use bioinformatics to study the genetic genealogy and genetic ancestry of Filipino heroes using the DNA of their living relatives, and to compare the genetic data with what is already established historically about our national heroes. This initiative aims to contribute to this very important historical discourse by providing the genetic perspective to genealogy and ancestry of those individuals who have clearly made their mark on our nation’s history. The proposed initiative aims to test the feasibility of the approach of tracing a Filipino’s genealogy and genetic ancestry by targeting lineage markers, e.g. mtDNA that is passed from mothers to children, and Y-DNA that is passed from fathers to sons. AIMs which are located in autosomes that a person inherits from one’s parents will also be included in the study. The study of genetic genealogy and ancestry is expected to contribute to the social discourse of defining the genetic relatedness of different groups of people, within and outside of the physical boundaries of our nation, thereby enriching the current knowledge of our past that could influence our future.

* * *

The author received the NAST Outstanding Young Scientist Award in 2003 for Molecular Biology. She is the current head of the DNA Analysis Laboratory, Natural Sciences Research Institute of UP Diliman, the director of the Program on Forensic and Ethnicity of the Philippine Genome Center, and leads the Innocence Project Philippines Network. In 2011, she was named as one of the first National Fellows of the L’Oreal Women in Science program because of her work in pushing for a greater understanding of Filipino genetics, including those of indigenous communities. She has appeared as expert witness in cases involving parentage issues. 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].