The nameless bodies often found at sea, not only in Cape Town but also all around the world, could soon be laid to rest with the help of the University of Cape Town’s (UCT) new study.
Cape Town’s Salt River mortuary frequently receives the remains of human bodies that have washed up on local beaches. The successful extraction of sufficient DNA continues to prove a difficult task and many who go lost at sea remain unnamed because of effect the ocean has on their bodies.
UCT is spearheading a new study that could be the key to resolving this local and worldwide challenge, bringing grieving families a sense of peace.
Directed by UCT’s departments of Human Biology and Pathology, the pilot study is making use of teeth to explore DNA preservation in a marine environment.
The study has been titled, “Can forensically usable DNA be successfully extracted from teeth submerged in False Bay, Cape Town? ”
This forms part of a larger research project on decomposition in the bay’s sea environment, according to Dr Victoria Gibbon, senior lecturer and biological anthropologist. More than 2 000 people drown in South Africa each year – 279 drownings occurring in the Western Cape – and many of these cases, the victims go unidentified.
DNA preservation and degradation
Gibbon says in most wash-up cases, visual and fingerprint identification is impossible, with identification via traditional anthropological methods similarly difficult due to extensive decomposition.
“In many cases, the remains that are washed ashore… have little soft tissue present,” she said.
Now, via the larger research project by Belinda Speed, who is completing her doctorate in forensic medicine, there is an opportunity to investigate DNA preservation and degradation in the marine environment.
Under the supervision of Gibbon and forensic science lecturer, Laura Heathfield, MPhil student, Chandra Finaughty, demonstrated a concept using pig’s teeth, preparing the samples for DNA extraction. If DNA could be extracted, further research would be necessary to apply the findings to a more accurate human model.
Heathfield says that nuclear DNA was the main molecular target in this study and in line with the fact that the South African Police Services (SAPS) Forensic Science Laboratories use only this type of DNA to generate a forensic DNA profile.
“However, in our study, positive results were found for mitochondrial DNA, which displayed better preservation over nuclear DNA in some samples,” she said.
Gibbon said SAPS and the country’s Forensic Pathology Services are unable to deal with the volume and complexity of many of the wash-up cases. This is attributed to a lack of research around the marine processes that affect the remains of an organism after it dies. This is called the taphonomic processes.
“Considering taphonomic processes are greatly influenced by environmental parameters such as sea temperature and scavenger activity, it is integral to study this process in specific geographical locations,” Gibbons said.
Gibbons also believes that further investigation of mitochondrial DNA preservation in the marine environment for use in routine forensic case work is also necessary going forward.
The study also exposed the need for collaborative research in the local region, considering the effects of area-specific variables and differences within marine ecosystems, have yet to be understood fully.
Gibbon is of the opinion that as long as these questions go unanswered, and it remains almost impossible to successfully recover DNA from the bodies of people who die at sea or are washed up on the beach, they will continue to be unidentified.
“DNA is often the only method of identification, and is used to confirm any probable identity. Therefore, the process needs optimisation and development on human samples,” she said
Gibbons says that they have applied for relevant funding to pursue this line of study as well.
A recent case where a skeleton washed up at sunset beach with the feet still intact could use the results of this as the identity of the person is yet to be confirmed despite the case being nearly a month old.