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Dig It: How DNA can be used to answer questions about ancestry

Whether DNA testing is used in the work at the Kamloops Indian Residential School is not for scientists, archaeologists or the general public to decide. It is an option. Listening to survivors, acknowledging the grief and trauma that is being experienced and ensuring that support is available is the focus.
Dig-It: How DNA can be used to answer questions about ancestry_0
This memorial is located in front of the former Kamloops Indian Residential School on the Tk’emlúps the Secwépemc First Nation.

The recent findings at the Kamloops Indian Residential School have prompted many questions.

There have been questions about what archaeology, and specifically forensic science, can do to assist with supporting the work that may lie ahead.

As Kukpi7 (Chief) Rosanne Casimir wrote in a June 10 update: “Tk’emlúps te Secwépemc Chief and Council have met internally and will continue to do so, to plan, organize and determine the best way forward.”

The update also indicated a “gathering of forensic archaeologist experts.”

One of the tools forensic archaeologists could utilize is deoxyribonucleic acid, commonly known as DNA.

This is not to say that DNA studies will be completed, but it is one tool that has been used by forensic experts to connect individuals to family members. However, DNA studies are not without some complications and may not always provide a clear result.

DNA is a complex molecule that contains all of the information to build and maintain an organism.

All living things have DNA within their cells and it is the primary unit of heredity in organisms of all types. What this means is that when an organism reproduces, a portion of their DNA is passed along to their offspring.

Once DNA is extracted from a sample in the laboratory setting, work begins to track ancestry. Paternal ancestry is seen by looking at the Y chromosome, which fathers pass to their male children. Mothers pass mitochondrial DNA to all of their children.

The process can be taken a step further by comparing the 22 non-sex chromosomes from the sample against a comparative sample or several samples.

In fact, DNA laboratories hold libraries of samples that are used to compare and determine to which groups in the library a DNA sample is most closely related.

The groups in the library are made up of samples from independent research and samples from people who have self-identified as a member of a particular group — West African, for example.

When a DNA sample is sent to a laboratory, that sample is compared with the groups in the library.

If anyone has sent their DNA to a company to trace ancestry, the results will read something like you are 23 per cent West African, 42 per cent French, 35 per cent British.

This is based on the probability that the DNA sample is most closely connected to the samples in those three groups.

As you can see, the methods for using DNA are only as good as the data in the libraries.

There are DNA laboratories that add new samples to their libraries. Individuals can submit DNA samples to laboratories to be tested against a sample.

For example, Kwaday Dan Ts’inchi, estimated to have died 300 years ago, was uncovered from a melting glacier in the territory of the Champagne and Aishihik First Nations. DNA from Kwaday Dan Ts’inchi was found to have the same common female ancestor as 17 individuals who provided their DNA and continue to reside in the area.

In this example, it was mitochondrial DNA, passed from mothers to all their offspring, that provided the connection.

Whether DNA testing is used in the work at the Kamloops Indian Residential School is not for scientists, archaeologists or the general public to decide. It is an option.

Listening to survivors, acknowledging the grief and trauma that is being experienced and ensuring that support is available is the focus.

Nadine Gray is a Kamloops-based archaeologist and  instructor at Thompson Rivers University. Dig It is KTW’s regularly published column on the history beneath our feet in the region. Interested in more? Go online to republicofarchaeology.ca.