Stone and Mark Stoneking conducted the DNA analysis that addressed these questions, reporting their results in the journal Ancient Biomolecules in 1996.

A Second Opening: What The Genes Held

The laboratory work on the Hourglass Cave samples faced the fundamental challenge that confronts all ancient DNA research: distinguishing authentic ancient genetic material from the modern contamination that inevitably finds its way onto archaeological specimens.

Human bone that has been handled — excavated, transported, analyzed — accumulates DNA from the hands, breath, and skin of every person who has touched it.

This modern DNA is abundant and easily amplified, and if it contaminates the ancient sample, it will appear as authentic ancient sequence in the final results.