The enamel above provides protection; the mineralized dentin matrix has proven to preserve molecular information better than most bone types.

And critically, the root canal — the inner passage that runs through the center of the root — can concentrate cellular material from the apex where blood vessels entered, potentially providing higher-quality ancient DNA than the surrounding dentin.

The sampling procedure involves drilling into the root of the tooth — carefully, to avoid contamination and to minimize destruction of the irreplaceable specimen — and extracting a small amount of powder from the interior.

This powder is then processed in the ancient DNA laboratory using the extraction and library preparation protocols described earlier.