DNA Unlocks Past Mysteries and Informs Present Conservation, Management and Social Justice Issues

November 01, 2021

Think 50 is old? Try 10,000

As SFU’s archaeology department marvels at turning 50, Dongya Yang, a professor in the department and associate dean of research for the Faculty of Environment appreciates much longer time scales. Using ancient DNA, he digs deep into the past to better understand the interactions of people and their environments up to 10,000 years ago.

Adding breadth to the Department

With a scientific background in zoology, Yang turned to anthropology for graduate studies to pursue an interest in understanding human interactions with their environments.  Yang then joined Archaeology to set up their DNA lab, adding another important specialization to the Department’s strong science foundation.

“Like forensic DNA fingerprinting, ancient DNA can be used to identify human remains in archaeological contexts, species of archaeological faunal remains, identify the sex of an animal, and see changes in population over time. For example, we can tell if a population is expanding or shrinking over time, or if some individuals moved in from another region,” explains Yang. 

Ancient DNA analysis has made many archaeological faunal remains invaluable sources of information and insights for current fisheries conservation and management practices. For example, Yang and his team have successfully recovered ancient DNA from salmon and herring (up to 10,000 years) along the Northwest Coast, opening new window of the past to actually witness long-term sustainable fishing practices of Indigenous peoples in BC for the past millennia.

Yang’s lab has also helped RCMP and BC Coronors Office to identify challenging human skeletal remains. Ancient DNA as a technique has proved to be very efficient in recovering DNA from difficult modern forensic remains, “this is because ancient DNA method is highly sensitive and always puts excellent contamination controls in place”, says Yang.        

Yang works at the forefront of advancing methods for ancient DNA extraction as well as protocols for decontamination and control and detection of contaminates to secure the authenticity of obtained ancient DNA data. These developments aid Yang in his research, while helping set standards for others in the field of ancient DNA analysis.

Expanding the application of DNA analysis

Shifting scales from entire populations to individuals, Hugo Cardoso is a Forensic Anthropologist in the department specializing in juvenile osteology.  He spearheads JUNO, the Juvenile Osteology Group who examine archaeological remains of children to understand developmental patterns shining light on past societies, and advancing methods of analyzing juvenile remains.

In modern cases, DNA analysis can be used in forensic contexts to identify human remains through a comparative DNA analysis of the deceased and their suspected family members. This technique generally serves as a last step in the identification process, following a series of methods that focus on the remains themselves.

As Co-Chair of Archaeology’s Forensic Research Centre, Cardoso specializes in these types of identifications known as medicolegal death investigations. Cardoso assists the coroner’s office, RCMP and provincial police departments in the recovery, identification, and determination of cause and manner of death when human remains are found.

Once the remains enter Hugo’s lab, he seeks to answer two fundamental questions: Who is this person? And how did they die?

Equipped with microscopes, x-rays and CT scans, Cardodo and his team look at pelvis shape to determine sex, joint condition to determine possible age ranges, and abnormalities such as healed fractures, implants and bone anatomy, to help identify the individual. When the remains display fresh fractures, cuts, or breaks, Cardoso determines direction of force or patterns of striation to identify if the injury was accidental or intentional and what object was involved.

“The techniques I use as a forensic anthropologist to identify someone are the exact same that I would use in archaeological contexts. The questions that I ask and the implications are what differ,” says Hugo.

The understanding of the juvenile skeleton and child development allows Cardoso to estimate the age of living children, helping to confirm the age or minority status of refugees or asylum seekers, victims of sex trafficking, or criminal responsibility so authorities can better address the case.

“These circumstances typically involve marginalized and illegal immigrant communities, where you can’t rely on documents to confirm the age of the individual. Within the legal system, there are different procedures, penalties or sentences that depend on whether they are a minor,” says Cardoso.

The work of Yang and Cardoso and their research teams reveals our ancient history but it also informs the recent past and our present as it contributes to social and ecological justice.

This is the second feature in a series celebrating Archaeology’s accomplishments over the past 50 years.