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Challenging DNA analysis process delays return of Jeju Air victims' remains

Published: 02 Jan. 2025, 14:33 Updated: 02 Jan. 2025, 19:14

Bereaved families of the victims of Sunday’s Jeju Air crash hold each other and grieve at Muan International Airport in Muan, South Jeolla, on Dec. 30. [JOINT PRESS CORPS]

Many sets of remains from the 179 victims of the Jeju Air crash have yet to be returned to their families due to difficulties in DNA testing, five days after the tragic accident on Dec. 29, despite the bodies being identified.

The delay is due to the lengthy process of collecting, analyzing and verifying fragmented remains before conducting autopsies, according to the National Forensic Service (NFS).

The Ministry of Land, Infrastructure and Transport said Thursday that the remains of some 30 victims had been returned to their families as of 3:30 p.m. that day. DNA analysis for 72 victims had been completed, including those that were returned.

NFS officials dispatched to the scene described the DNA analysis process and challenges they face to the JoongAng Ilbo, an affiliate of the Korea JoongAng Daily. The NFS has deployed over 50 personnel, including medical examiners, investigators and a genetic analysis team, to identify the remains.

“We are working tirelessly night and day to return the victims to their families as soon as possible,” said an NFS official responsible for DNA analysis.

Bereaved families of Jeju Air crash victims visit the tragedy site at Muan International Airport in South Jeolla on Dec. 31. [YONHAP]

The NFS is using short tandem repeat (STR) analysis, the international standard for DNA identification, to determine the identities of the victims. STR analysis compares the repetitive sequences at specific locations in DNA, which vary from person to person, effectively serving as a "DNA fingerprint."

STR analysis starts with the police collecting reference samples from the victims' families, such as epithelial cells from the mouth. Then, the medical examiner is dispatched to the disaster site to collect samples from the victims' remains.

The samples are then sent to the NFS headquarters in Wonju, Gangwon, for analysis using DNA sequencing machines. DNA results for individual victims can be obtained in as little as a few hours.

Bereaved families of victims who died in the Jeju Air crash express their sorrow at Muan International Airport in South Jeolla on Dec. 30. [JOINT PRESS CORPS]

The most significant hurdle in the identification process is matching highly fragmented remains. With 607 fragments already recovered and the potential for more to be found, cross-referencing and analyzing each fragment takes time.

“We have to compare and analyze fragments one by one because we don’t know which ones belong to which victim,” an NFS official explained. Once the remains are consolidated, DNA samples from families are cross-checked to confirm relationships. Finally, the remains undergo autopsy and inspection before being handed over to the police for release to families.

The process is further complicated by cases involving siblings among the victims. Standard STR analysis may not suffice in such cases, requiring additional testing such as Y-STR analysis for paternal lineage or mitochondrial DNA analysis for maternal lineage.

Acting President Choi Sang-mok, center, meets with bereaved families of Jeju Air disaster victims at Muan International Airport in South Jeolla on Dec. 30. [MINISTRY OF ECONOMY AND FINANCE]

DNA degradation is minimal in the case of the Jeju Air crash, unlike typical fire-related incidents where high temperatures can severely damage genetic material.

“Our goal is to recover every piece, down to a single finger, and return it to the bereaved families,” said an NFS medical examiner.

On Dec. 31, the NFS conducted autopsies of the pilot and co-pilot at the Gwangju branch of the NFS. This routine procedure aims to determine whether factors such as alcohol, drugs or toxic gases contributed to the disaster.

Bereaved families of the victims of Sunday’s Jeju Air crash hold each other and grieve at Muan International Airport in Muan, South Jeolla, on Dec. 30. [JOINT PRESS CORPS]

No abnormalities have been detected by the autopsy so far. The autopsies were performed as a precaution as the two were operating the aircraft, mirroring investigations from a 2011 crash involving an Asiana Airlines cargo plane near Jeju Island.

A briefing was held on Wednesday at Muan International Airport’s terminal. Families, many of whom stayed awake overnight, demanded more transparent communication and explanations from the government regarding delays in releasing remains.

“We must confirm the DNA of the main remains to determine the ownership of additional fragments,” said Na Won-oh, chief of the Jeonnam Provincial Police Agency’s investigation department, in response to suggestions of foregoing the identifications of body fragments.

“If we leave fragments unidentified, they will remain labeled as ‘unknown,’ which is unacceptable,” said Na. “It’s ideal to verify both the main remains and fragments, even if it takes more time."

BY JUNG SI-NAE, KIM MIN-YOUNG [[email protected]]