Ancient DNA reveals northwest range extension of Richardson's ground squirrel (Urocitellus richardsonii) into northeastern British Columbia, Canada, during the Late Pleistocene

摘要

Ancient DNA was extracted from 12 500 to 10 500 year old ground squirrel bones from Tse'K'wa, an archaeological site in the Peace River region of northeastern British Columbia, Canada. Analysis of mitochondrial DNA from seven individuals demonstrates that all are Urocitellus richardsonii (Richardson's ground squirrel), a species not found in the region today. Phylogenetic and sequence analyses indicate these individuals share a previously undocumented mitochondrial control region haplotype that is most closely related to haplotypes observed in modern specimens from Saskatchewan and Montana. At the end of the Pleistocene these ground squirrels extended their range north and west into open vegetation communities that developed when ice sheets melted and glacial lakes drained. They were subsequently extirpated from the Peace River region when forests replaced earlier pioneering vegetation communities.