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Ancient DNA recovered from dire wolf and coyote teeth at La Brea

Recovered fossil dire wolf skulls from La Brea Tar Pits displayed in a museum
Research · Genetics & genomics

Researchers have for the first time confirmed DNA from the fossil animals themselves in fossils from an asphalt deposit. The fragments came from teeth of two dire wolves (Aenocyon dirus) and a coyote (Canis latrans) from Rancho La Brea in Los Angeles. Only three of ten DNA extracts from tooth material yielded authentic animal DNA, far too little to reconstruct a genome.

The teeth came from Project 23, Box 9, a deposit containing fossils about 40,000 to more than 55,000 years old. They were excavated without treatments such as solvents that can damage DNA. Even so, the animal DNA signal was tiny amid contamination and other DNA.

Targeting mitochondrial DNA

Broad sequencing of DNA in the samples recovered fewer useful fragments than a method that selectively enriched mitochondrial DNA. Cells contain many copies of mitochondrial DNA, so it can be easier to find when most genetic material has degraded. Residual asphalt did not prevent DNA amplification or targeted enrichment in these tests.

Several possible causes of poor preservation

Warmth and moisture can speed DNA breakdown. The researchers considered the fossils’ “thermal age”—the cumulative effect of temperature over time—as one possible factor. Gypsum, calcite and clay coatings in the sediments also point to groundwater movement and changes in soil conditions, which may affect how molecules survive. Temperature shifts can change asphalt’s viscosity, making it soften and harden over time.

Collagen, a durable structural protein in bone, did not reliably indicate whether DNA had survived. Preserving one molecule does not guarantee that a more fragile one remains. The study cannot identify which factors mattered most, but its findings show why both a fossil’s burial history and its later collection and treatment matter when selecting samples for ancient-DNA research.

Sources and image credit

  1. Temperature, taphonomy, or technique? Contrasting hypotheses of ancient DNA recovery from Quaternary asphaltic fossil depositsOriginal open-access research article first published online 1 October 2026. Publisher's full-text preview and detailed sections were checked for the 3/10 positive extracts, targeted mitochondrial capture, collagen contrast, temperature/groundwater/asphalt hypotheses and source limitations.

Image: Fossil dire wolf skulls recovered at La Brea Tar Pits, Los Angeles. Photo: Bill Abbott / Wikimedia Commons, CC BY-SA 2.0. Illustrative fossils, not confirmed as the study specimens. · CC BY-SA 2.0 · Source

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