Meticulously extracting DNA samples from each set of remains
Responding to the 500-day and night campaign to search, repatriate and identify martyrs' remains launched by the National Steering Committee 515, Dr. Vuong Gia Bao, forensic expert of the Ho Chi Minh City Forensic Center, volunteered and was fortunate to be selected to participate in supporting the collection of DNA biological products of martyrs' remains at Le Thi Rieng Park.
The work takes place regularly during office hours, starting from 7:30 am to about 4:00 pm - 5:00 pm. Early in the morning, Dr. Bao cleans the space and prepares specialized equipment carefully. When functional forces bring the found remains to the sample room, the examiners will meticulously dissect, clean mud and carefully classify each bone segment. This step requires high concentration to ensure accuracy, absolutely not to mix different sets of remains.
Because bones buried underground for many years have heavily decomposed, doctors are required to prioritize choosing the femurs, tibias and teeth, the hardest parts, playing the role of "arms" protecting the genetic structure inside. Only when teeth are not found or there is no other choice, the team must use porous bone fragments. The sample after being taken is cleaned and stored in a preservation box at room temperature of 20 - 25 degrees C.
According to Dr. Vuong Gia Bao, extracting DNA from tooth and bone samples is an extremely complex technique. A solid calcium layer, although helping to protect DNA from environmental destruction, is also a solid "wall", requiring a specific set of chemicals to break it down. At the same time, bones that have been underground for many years are very easily soaked in impurities. If not washed and cleaned meticulously, these impurities will hinder the reaction of machines, damaging the entire analysis process.
However, cleaning samples is only the beginning. After nearly 60 years buried underground, most of the nuclear DNA (DNA located in the cell core) inside the bone samples have been broken and decomposed. To overcome this barrier, experts are forced to find alternative solutions: decoding mitochondrial DNA.
In terms of science, if ordinary DNA is very easily damaged over time, then mitochondrial DNA is like "backup copies" with abundant quantity and superior durability. This characteristic significantly improves the rate of successful detachment and identification profiles from long-standing skeletons.
However, mitochondrial DNA has strict genetic laws: only passed down through the mother line. Therefore, to have data to compare and identify martyrs, biological samples must be collected from relatives on the maternal side (such as biological mother, maternal grandmother, siblings of the same mother, or children of sisters/brothers of martyrs).
After taking samples, the biological products are brought to the laboratory to grind into fine powder and use chemicals to filter out pure DNA. This meager amount of DNA will be "cloned" many times, then put into an analyzer to create a complete genetic profile. Testing time is not fixed; if the sample is bad and the machine cannot read the signal, the examiners must persistently test again and again until the sample is exhausted.
Wondering about the limits of science and the command from the heart
Finding the remains is only halfway through, and DNA is the last "golden door" to bring the heroic martyrs back to their families.
According to Dr. Vuong Gia Bao, the biggest concern of a forensic expert is when encountering bone samples that are sturdy on the outside but do not give a genetic signal when put into analysis.
Standing before the limits of science, regret did not make the whole team flinch, but on the contrary, it further urged them to try their best. Instead of giving up, the examiners persistently did it over and over again, cherishing every bone fragment, every bit of the last biological product with the faintest hope.
We always tell ourselves to try our best, do everything possible so as not to regret or be ashamed of the great sacrifice of previous generations," Dr. Bao confided.
For more than a week, the working rhythm of the sample taking team has always been maintained in a hurry from early morning to late afternoon. For each member, this is not simply a dry forensic procedure, but an order from the heart, a deep gratitude of the young generation to those who fell for national independence. All share a high determination: dedicating all their strength and meticulousness in every smallest operation to keep every opportunity to identify identities, with the greatest desire to soon bring them back to their homeland and family.
