DNA preservation in highly degraded skeletal remains from the Vietnam war-Characterization and DNA extraction...

Recent advances in forensic genetics in NGS-based targeted SNP typing have opened new opportunities for the identification of highly degraded skeletal remains. This is particularly the case for missing from the Vietnam War, where DNA degradation and the need for distant kinship matching render STR testing largely ineffective. Hundreds of thousands of cases of Vietnamese combatants are unaccounted for from the conflict, yet there is still a profound societal desire to address the issue of the missing. The Vietnam government is committed to the development and application of modern methods for large scale identification, in an effort that requires adaptation and implementation of NGS-based SNP typing to the Vietnam context. A primary first step is to characterize the nuclear DNA preservation in skeletal remains from the conflict and to demonstrate the ability to effectively extract nuclear DNA. Here we report an analysis of DNA preservation from a representative study set of 100 bone samples, to serve as a baseline for planning a large program of database-driven DNA identification. This is a joint capacity building project, with methods development initiated at the International Commission on Missing Persons (ICMP) DNA Laboratories and then coupled with formal training, implementation, and concordance testing in the Center for DNA Identification (CDI) laboratory of Vietnam. With newly adapted DNA extraction methods fully implemented at CDI, we report human autosomal DNA recovered from 70 % of the bone samples. We report also a correlative analysis of DNA preservation with respect to a set of 7 systematically scored morphological characteristics of the bone samples. These results support the feasibility of a new approach to large scale DNA identifications in Vietnam.