The authors acknowledged the limitations of mitochondrial DNA analysis — specifically, that mitochondrial DNA establishes maternal lineage but does not provide a complete picture of biological ancestry, does not identify individuals, and cannot establish cultural affiliation with any specific modern community.

They acknowledged that the coprolite identification was based on a combination of physical morphology, dietary content, and the DNA results themselves.

They acknowledged that contamination was an ever-present concern in ancient DNA work and described the precautions taken.

But the headline result was impossible to misunderstand: human DNA in directly dated coprolites from a layer older than Clovis, from the Oregon Great Basin.

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