Ancient DNA Study Reveals Dispersal Patterns and Diversity Changes in North American Deer Species
Researchers used ancient, historical, and modern DNA samples to reconstruct the evolutionary histories of North America's five extant cervid species — caribou, moose, wapiti, white-tailed deer, and mule deer. The study found that moose and wapiti expanded rapidly after arriving on the continent, while wapiti later lost genetic diversity, and eastern Canadian caribou share ancestry with a 30,000-year-old western Canadian specimen. The findings highlight how glacial cycles, human migrations, and European colonization have shaped the genetic makeup of these species over millennia, with implications for conservation.
A new preprint study posted to bioRxiv analyzed DNA from ancient, historical, and modern individuals of North America's five cervid species to trace their demographic and evolutionary histories across roughly two million years. The research found that moose and wapiti (elk) underwent rapid population expansions following their dispersal onto the continent, but wapiti subsequently experienced a significant loss of genetic diversity. Caribou in eastern Canada were found to share ancestry with a sample dating back approximately 30,000 years from western Canada, suggesting long-range connectivity across the continent in deep prehistory. The study also documents rapid diversification in Odocoileus deer — the genus containing white-tailed and mule deer — leading to incomplete lineage sorting and mito-nuclear discordance, a phenomenon where mitochondrial and nuclear DNA tell conflicting evolutionary stories. The authors argue that chronological sampling — combining ancient, historical, and contemporary specimens — is a powerful tool for understanding how external pressures such as climate change, human arrival, and colonization drive genomic change over time.
What's missing
As a preprint, this study has not yet undergone peer review, so its methods and conclusions have not been independently validated. Key open questions include the specific mechanisms driving wapiti's post-arrival diversity loss (e.g., hunting pressure vs. climate), and whether the eastern-western caribou ancestry connection reflects continuous gene flow or a single dispersal event.
What different sources said
- bioRxivCenter
Ancient DNA perspectives on North American cervids identify dispersal waves and fluctuations in diversity
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