Returning Martyrs' Names: Research to Find New Sequencing Technologies for DNA Identification
Identification of the remains of martyrs lacking information is a political task of humanitarian significance, always directed by the Party and Government to solve. However, DNA testing of martyrs' remains still faces many difficulties, requiring close cooperation between domestic and foreign inspection units and organizations as well as finding new technologies to make this work more effective.
The examiner of Center for DNA Identification (Institute of Biotechnology, Vietnam Academy of Science and Technology) analyzes a sample of martyrs' remains - Photo: Hoang Giang
Prime Minister Pham Minh Chinh once affirmed that the search, gathering and identification of the remains of martyrs is a political task, the responsibility of the whole Party, the whole people and the whole army; We need to do this job well with all our heart and responsibility.
In the 7th month of paying tribute to heroes and martyrs, reporters visited the Center for DNA Identification (Institute of Biotechnology, Vietnam Academy of Science and Technology) to understand, through the stories shared at the Center, the difficulty of the journey to find the name of a martyr. Those were the days when the Center's inspectors in protective suits drenched themselves in the rain and sun for days in martyrs' cemeteries to excavate each unnamed martyr's grave. It was many hours, also in tight protective suits, the brothers diligently sat down to process a specimen that was the tooth of the deceased and it was also the sadness of taking weeks to process the sample but finally could not get to the DNA.
Dr. Hoang Ha, Director of Center for DNA Identification, said that in recent years, the Center has attracted a team of young and qualified staff. They work in harsh and specific conditions but are always enthusiastic with the desire to contribute their efforts to the work of reparation, responding to the heroic martyrs and heroic Vietnamese mothers. According to statistics, the country currently has about 300,000 samples of martyrs' remains that are missing information that has not been identified. At Center for DNA Identification, there are nearly 6,000 samples, of which about 4,000 have been analyzed and 2,000 are awaiting analysis.
The process of testing DNA for remains is quite complicated. From the bone sample, technicians must clean the surface, dry it and then chop it, then take a tartar brush to continue cleaning the surface. The cleaning work lasted a whole week. The sample is then soaked in chemicals and then crushed, amplified DNA and sequenced. Moreover, the remains are collected and buried in many cemeteries across the country, and the soil and climatic conditions in different regions can cause different effects on the quality of the samples. The martyrs died for a long time, so most of the samples were badly decomposed and the quality of the samples deteriorated rapidly, many samples had to be analyzed many times. Therefore, it is not possible to use one or several technological processes to apply to all models, but it is always necessary to develop, optimize and test new processes.
In addition, the lack of a centralized database makes the process of matching with remains data inefficient. Currently, forensic units in Vietnam mainly use the 1-1 matching method between mitochondrial DNA profiles of martyrs' remains and martyrs' relatives in each specific case.
Large-scale identification of martyrs' remains requires the construction of databases for storage and exploitation, not only mitochondrial DNA data but also nuclear DNA data (e.g. STR, SNP). In addition, data on relatives of martyrs are very limited, mainly from single cases. Many relatives of the martyrs are elderly, many have died, so it is necessary to speed up the assessment process. The current cost of DNA testing is at VND 4,685 million / sample and the test results are still very low compared to actual requirements. The inspection samples were carried out many times but did not produce results without a mechanism to pay the cost of materials, chemicals and labor.
Scientists are highly determined to meet the aspirations of the Party, the Government as well as the people on the issue of identifying the remains of martyrs who lack information, and specially to pay tribute to the sacrifices of martyr heroes - Photo: Hoang Giang
New technology directions for inspection of difficult samples
Dr. Hoang Ha said that currently, the main genetic testing method applied to the remains used at the Center and other testing units in Vietnam is mitochondrial DNA analysis. Although this method has supported many conclusions of identification, the process of DNA testing of remains faced many challenges as the number of samples was large and the quality of samples decreased. The effectiveness of current DNA extraction methods for strongly degradable samples is decreasing. In addition, mitochondrial DNA has a low ability to distinguish individuals due to the high probability of coincidence of mitochondrial DNA profiles in the population, so mitochondrial DNA data cannot be used independently, but needs to combine other evidence before drawing identification conclusions.
During this period, the Center is cooperating with the International Examination Organization (International Committee for the Search of Missing Persons - ICMP) to test new DNA extraction technologies and a gene sequencing technology called MPSplex SNP. These technologies are specifically designed to identify missing persons and have potential applications for severely decomposed, fragmented DNA samples. "This is very effective in examining difficult samples such as those of Vietnamese martyrs, when DNA from the samples has been severely damaged," Dr. Hoang Ha shared. ICMP's DNA extraction process uses a total demineralization technique of bone samples and uses special membranes to concentrate DNA, enhancing the content of short-sized DNA fragments collected in the extraction fluid. In addition, the process has been adapted to automated extraction systems for partial automation.
For the new sequencing technology, the use of SNPs — a type of molecular marker in a nuclear gene — could lead to definitive identification conclusions between the sample not only with close relatives but also with distant relatives. This approach shows the suitability of the Vietnamese situation, when the father, mother, brother, sister and sister of the martyr are old, many have died. MPSplex with its very large number (more than 1,400) of SNP molecular indicators, operating at high throughput on automated systems, shows potential in large-scale identification of Vietnamese martyrs' remains.
According to Dr. Hoang Ha, these are new and modern technologies, requiring advanced machinery, chemicals and supplies, the inspection process consists of many steps with technical operations that need high accuracy, thus requiring competent and experienced inspectors. The adoption of these technologies needs to take place in many steps from small scale to large scale. In the near future, the Center will conduct trials of a number of DNA extraction processes at the laboratory with the support of equipment, machinery, chemicals and materials from ICMP to have initial assessments of the effectiveness and applicability of these processes in Vietnam.
According to the plan, the testing of DNA extraction and gene sequencing technology in Vietnam will be conducted in several phases within 2 years, starting from July 2023.
"The identification of the remains of martyrs lacking information is a particularly meaningful political task, which has always been directed and supported by the Party, the Government, concerned ministries and branches. With the cooperation between domestic and foreign assessment units and organizations, we hope that the progress of the examination of the remains of martyrs will be strengthened and achieve high efficiency," Dr. Hoang Ha said. The Center also wishes to receive more technical and financial support from organizations, businesses domestically and internationally in order to ensure the improvement of assessment capacity, expansion of laboratories, updating research at the world technological level for the DNA testing process of martyrs' remains in accordance with Vietnam's conditions.
In the first 6 months of 2023, Center for DNA Identification (Institute of Biotechnology) has received 132 samples of martyrs' remains from 4 martyrs' cemeteries and cases of articulated comparison samples between relatives and martyrs' remains. In collaboration with ICMP, 100 bone samples of different decomposition levels were analyzed to optimize the extraction of DNA from the nucleus. This result will be an important basis in the development of a new methodology to improve inspection capacity and efficiency. The center has also successfully developed and published internationally a study involving DNA analysis of bone samples dating back more than 4,000 years. This is the basis that opens a new direction of research, archaeological genetics.
Translated by Phuong Ha
Link to Vietnamese version