1. Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, Ontario, K1N 6N5 Canada.
2. Paleoecological Environmental Assessment and Research Laboratory, Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6 Canada.
3. Canadian Wildlife Service, Environment Canada, Iqaluit, Nunavut, X0A 0H0 Canada.
4. Department of Geology, University of Toronto, Toronto, Ontario, M5S 3B1 Canada.