Wayanad’s missing list: How forensic teams are using DNA clues to join the dots

At the end of the week-long rescue operations, 231 bodies were recovered and 118 persons were declared missing. The missing were feared dead and as their families waited for closure, forensic teams in the state got down to identifying them through DNA tests.

The unidentified bodies and body parts, each with a specific number for future identification, were buried at the mass burial ground at Puthumala, barely 5 km away from Chooralmala, one of the worst-hit villages. Before the bodies and body parts were lowered into the pit, samples from these were taken for DNA tests. As many as 421 samples were dispatched to the lab in Kannur.

According to State Forensic Science Laboratory Director Dr Pradeep Saji K, testing such a huge number of samples in a short period was a major task for the team at the regional lab in Kannur, which has one of the best DNA testing facilities in India.

The unidentified bodies and body parts, each with a specific number for future identification, were buried at the mass burial ground at Puthumala, barely 5 km away from Chooralmala, one of the worst-hit villages.

“We mobilised our people from other districts and they worked day and night for several days. The samples (kept in preservatives) were put in the cold room at the lab where we ensured that there is no cross contamination. Now, we have almost completed the testing process,’’ he said.

Explaining the DNA testing process, Bushra Beegum, joint director at the lab in Kannur, said, “Most of the samples for DNA testing were taken from bones of unidentified bodies. In some cases, the samples were taken from teeth and body tissue. DNA extraction in the case of bones is the most time consuming – the bone has to be cleaned to take out the bone marrow. It is a skilled, delicate, manual job which can take up to four hours.”

On the many challenges the team encountered, Beegum said, “We need at least .1 nanogram of DNA to create a profile (a pattern of DNA sequences that identifies an individual). Many tissue samples collected from the river were putrefied and did not have that minimum quantity of DNA that we needed for sequencing,’’ she said.

In some cases, the samples were taken from teeth and body tissue. (PTI)

After the DNA samples are sequenced, the next step is comparison, where samples with similar DNAs (since several body parts are tested) are put into different groups.

“Thus, we got around 60 groups, with each group finally coming together as different body parts of an individual. Then, we compare these grouped samples with the DNA profile of the blood samples collected from relatives of the missing persons. When a new sample from a newly recovered body part reaches our lab for testing, we do their DNA profiling and see if it matches any of the existing groups,’’ said the joint director.

Talking of the other challenges they faced, an official said that several families had perished in the tragedy, police teams were sent out to look for extended relatives. In some cases, family trees of the victims were drawn and shared with the team engaged in collecting blood samples.

Forensic experts also said that since all the victims were from a particular region (Mundakkai and Chooralmala), there is a high possibility that inbreeding might have taken place over generations. “Normally, of the 46 chromosomes of a person, four chromosomes are unique to that person. But in many samples tested from this particular region, a decrease in the differences between their chromosomes were noticed. This is mainly due to inbreeding, which happens when distant relatives marry,’’ said an expert familiar with the work at the Kannur forensic lab.

Kilometres away, in Wayanad, among those awaiting closure is Safad Kunnath, 24. He has just registered three missing complaints at the Meppadi police station – the bodies of his father Hamsa K, a plantation worker, mother Jumaila and younger brother Hasin Muhamed, have been untraceable since the tragedy.

“Two rounds of DNA results are out, but my family is still missing. I was told to wait a while for the entire process to be completed, after which the death certificates will be issued,’’ said Safad, who works at a coaching institute in Thrissur.

“All I have done is wait. First at hospitals, waiting for bodies of my father, mother and brother. Then at the make-shift morgue in Meppadi. And now, for the DNA results. If they were identified among those buried at the common burial ground at Puthumala, it would be a

relief for us. Otherwise, the thought that my parents and brother are still buried somewhere under the boulders is painful,’’ he says.