Scientists have extracted and analyzed 34 new mammoth (Mammuthus spp.) mitochondrial genomes, including two Early Pleistocene and nine Middle Pleistocene mammoth specimens from Siberia and North America. They have identified the oldest known mammoth DNA in North America, from a 200,000-year-old specimen found in the Old Crow River, Yukon Territory, Canada. The results confirm previous research, showing that mammoths from around a million years ago do not closely resemble later mammoths.
Life reconstruction of the steppe mammoth (Mammuthus trogontherii). Image credit: Beth Zaiken / Centre for Palaeogenetics.
Ancient DNA recovered from specimens dated to the Early Pleistocene (2.6 million to 780,000 years ago) and Middle Pleistocene (780,000 to 126,000 years ago) stages has the potential to allow the direct study of the deep-time evolutionary events that are key to understanding species formation.
Unfortunately, access to such deep-time DNA is limited, and so far only a handful of studies have been able to obtain either genome-wide data or complete mitochondrial genomes (mitogenomes) from deep-time specimens.
“Our analyses provide an unprecedented glimpse into how major deep-time demographic events might have shaped the genetic diversity of mammoths through time”, said Dr J. Camilo Chacón-Duque, a researcher at Stockholm University.
By analyzing 34 new mammoth mitogenomes alongside over 200 previously published mammoth mitogenomes, the researchers were able to find that diversification events across mammoth lineages seem to coincide with well described demographic changes during the Early and Middle Pleistocene.
Their findings support an ancient Siberian origin for major mammoth lineages and reveal how shifts in population dynamics might have contributed to the expansion and contraction of distinct genetic clades.
“With the ever-decreasing costs of sequencing technologies, mitogenomes have been somewhat forgotten. However, our study shows that they remain crucial for evolutionary biology since they are more abundant than nuclear DNA,” said Dr. Jessica A. Thomas Thorpe, a researcher at the Wellcome Sanger Genome Institute.
The current study not only advances our understanding of mammoth evolution but also contributes to the broader field of ancient DNA research.
The scientists developed and applied an improved molecular clock dating framework, refining how genetic data can be used to estimate the ages of specimens beyond the radiocarbon dating limit.
This methodological advancement offers a powerful tool for future research on extinct and endangered species.
“These results add to our earlier work where we reported million-year-old genomes for the first time,” said Professor Love Dalén, a researcher at Stockholm University.
“I’m very excited that now we have genetic data from many more mammoth specimens sampled across the last million years, which helps us understand how mammoth diversity has changed through time.”
The team’s results were published in the journal Molecular Biology and Evolution.
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J. Camilo Chacón-Duque et al. 2025. A Million Years of Mammoth Mitogenome Evolution. Molecular Biology and Evolution 42 (4): msaf065; doi: 10.1093/molbev/msaf065
