Recently, we had the opportunity to collect frozen bone remains directly from the permafrost in Canada, as part of our research on the evolution of flora and megafauna throughout the climate variations of the late Pleistocene (~10 to 100 thousand years ago). The two of us, along with ACAD director, Alan Cooper, travelled to the gold rush city of Dawson in the Yukon, where a few families are still mining for gold in the frozen soil. To reach the gold-rich layers, miners are using high-pressure water to accelerate the natural thawing of the permafrost, uncovering numerous fossil bones (our gold mine!) in the process. Most of these bones are from large mammals who were grazing in the steppes of the Berigian region a few millennia ago: mammoths, horses, and bison; though the burrows of ancient squirrels also survive, with fascinating plant material inside.
A team of palaeontologists, lead by Dr. Grant Zazula, work throughout the summer months each year to gather these precious remains, and, in 2014, we were invited to join them. Our goal was to collect frozen samples for ancient DNA analysis. When it comes to ancient DNA, preservation is paramount to obtaining quality data. Dry, freezing temperatures are the best conditions, so bones buried for thousands of years in deep-frozen soil are the ultimate find!
It is a hallowed and humbling moment, while digging through smelly, muddy permafrost, when you discover a whole bison skull, mammoth tooth, or squirrel midden. You know that these samples are going to provide genetic data at the genomic scale; helping us answer otherwise undecipherable questions about the evolution of plants and mammals during and in between glaciation periods. DNA from specimens such as these are the only way humans can begin to understand the world as it was when these plants and animals dominated the landscape.
These important finds have been returned to ACAD’s quarantine ancient DNA lab, where we can begin mining for our own gold: DNA.