The tragic Air India plane crash in Ahmedabad on June 12, 2025, has prompted a large-scale forensic effort to identify the deceased. With many bodies severely burned and fragmented, DNA testing has become crucial in providing closure to grieving families. Authorities are working tirelessly, employing advanced techniques to match DNA samples from the remains with those of relatives. Here’s a detailed explanation of the DNA testing process used in such circumstances.
Collection of Samples
The first step involves collecting DNA samples from both the victims and their relatives. According to the FSL (Forensic Science Laboratory) Director HP Sanghvi, there are two primary methods for DNA sampling. The easier method involves collecting fresh blood samples from relatives. However, extracting DNA from the remains of the deceased is more complex, especially when the bodies are severely damaged. In such cases, samples like bones and teeth are meticulously collected.
Extraction and Preparation
The collected samples from the deceased undergo a thorough cleaning process to eliminate any external contamination. If the sample is a bone, it is powdered. If it's a tooth, it is broken into fragments and then powdered. This pulverization is essential to access the DNA within the cells. The DNA is then isolated using specialized machines at controlled temperatures to prevent degradation.
DNA Analysis
After extraction, the DNA undergoes quality and quantity analysis using RT-PCR (Real-Time Polymerase Chain Reaction) machines. This step is crucial to ensure that the DNA is of sufficient quality and quantity for further testing. If the DNA meets the required thresholds, multiple copies are generated through a process called DNA amplification. This amplification ensures there is enough DNA to perform the necessary analyses. The DNA strands are then separated and run through sequencing machines to generate a full genetic profile. This profile consists of specific regions of the genome known as short tandem repeats (STRs), which vary significantly among individuals, making each person's DNA profile unique.
Matching and Identification
The generated DNA profile from the victim's remains is then compared with the DNA profiles of their family members. According to Sanghvi, a confirmation can only be made when 23 alleles (specific locations on a chromosome) match between the victim and their family members. In cases involving a father and son, further Y-chromosome testing is performed to establish identity due to the shared Y-chromosome.
Challenges and Accuracy
Despite the advanced techniques, the process is not without its challenges. If sufficient DNA alleles are not detected, the entire process must be restarted. However, forensic scientists can often retrieve DNA from bones or small fragments, even if the tissue is charred. Dr. Mishra stated that forensic scientists have successfully extracted DNA from ancient remains, including Neanderthals. Each person has a unique DNA signature. While the DNA alone cannot reveal the name of the person, it can confirm their identity by comparing it with samples from relatives.
Speed and Efficiency
In emergency situations like the Air India plane crash, time is of the essence. According to Dr. Mishra, DNA fingerprinting can be completed in as little as a day if fast-tracked. While DNA isolation takes a couple of hours, the rest of the analysis can be done within a few more. Under standard conditions, it usually takes a couple of days.
Current Status
As of June 15, 2025, authorities have identified 47 victims of the Ahmedabad plane crash through DNA matching, and the bodies of 24 victims have been handed over to their families. Teams from the State Forensic Science Laboratory (FSL) unit and National Forensic Sciences University (NFSU) are working to match more DNA samples.
The DNA testing process is a meticulous and complex undertaking, but it provides a reliable method for identifying victims in mass disasters like the Air India plane crash. The process offers solace and closure to grieving families during this difficult time.
