To biologists, the beaver is known as Castor canadensis. Its scientific name flaunts unabashed ties to Canada. Its common English name, however, is the “North American beaver.”
The animal attracted shiploads of Europeans to North America, where they reshaped the landscape — in much the same way beavers reshape wetland environments. However, Canada specifically acknowledged the role the large, smelly, flat-tailed rodent played (albeit reluctantly) in shaping European headgear and this country’s development. In 1937, the country made the beaver the go-to imprint on the nickel.
Another milestone in Canada’s claim to the beaver occurred this year, when Canadian researchers published the animal’s genome sequence.
The leader of the research team, University of Toronto molecular genetics professor Stephen Scherer, says he chose the beaver genome because of Canada’s 150th anniversary and to “mark our territory.”
After starting his work, Scherer learned researchers in Oregon were working on the North American Beaver Genome Project. He challenged his Canadian team to be first.
Six months later, they completed the sequence.
Making the victory even more Canadian, the team sequenced the genome using a new, made-in-Canada approach.
Ward is the 10-year-old beaver from the Toronto Zoo that donated tissue samples to the project. The new method allowed the scientists to assemble Ward’s genome from the ground up without relying on a reference genome.
Researchers first constructed a rough draft of Ward’s genome with long fragments of his DNA, then fleshed it out with shorter fragments. They then assembled the sum of messenger RNA found in Ward’s blood and tissue samples to serve as a scaffold for the genome.
Messenger RNA molecules carry precise recipes for beaver proteins from Ward’s DNA to his cellular protein-building machinery. Finally, the scientists compared their results with related mammal genomes and corrected the sequence manually.
According to the results, the genome of Castor canadensis — or the North America beaver — comprises 2.7 billion base pairs, which reside in the 40 pairs of chromosomes within the nucleus of each of Ward’s cells. That’s slightly less than the approximately three billion base pairs found in the human genome. Each chromosome contains hundreds to thousands of genes, which carry the detailed instructions for making beavers beavers — or humans humans — and offers insights into how the animal evolved in North America’s environments through time.
This is only the latest incident of Canadians scent-marking the beaver as a significant part of our historic, cultural and now scientific territory, but Canada has been part of the genome-sequencing movement since 1998, when it announced the Canadian Biotechnology Strategy, formed Genome Canada, and joined the Human Genome Project. British Columbia is home to one of Genome Canada’s technology centres, and Canadian researchers are exploring how genomics can be used to fight disease, maintain health and safeguard forests, crops, and other species from invasive pests and climate change.
For example, scientists from B.C., France, Israel, the U.S. and elsewhere recently finished sequencing the sunflower genome — “one of the most challenging genomes published to date,” says UBC professor Loren Rieseberg, a senior researcher.
As the only major crop domesticated in North America, the sunflower provides much fodder for research. It serves as a model for how new species arise and for understanding solar tracking and plant growth.
“Not only have we sequenced the sunflower’s genome, but we have also built physical and genetic maps of its structure, which increases the genome’s value for research and breeding.”
This lays the foundation for work to use the sunflower’s stress resistance and ability to grow in different climates and conditions, including drought, to adapt other crops to climate change.
These are two recent genomic advances Canadians helped make happen. Perhaps, at some point in the future, genomics research will become as much a part of the Canadian identity as Castor canadensis is.
