Ancient DNA analysis requires working in environments that are as free as possible from modern human DNA, which is present essentially everywhere that human beings work and live.

Any lapse in contamination control risks introducing modern sequences into the analysis that could be mistaken for authentic ancient sequences.

The results were significant.

Mitochondrial DNA was recovered from multiple coprolite specimens.

The sequences identified belonged to haplogroups that are recognized as Native American founding lineages — specifically haplogroup A2 and haplogroup B2, which are among the maternal lineages that trace their origin to the ancestral populations that crossed into the Americas from northeastern Asia through Beringia.

The radiocarbon dates associated with the human-positive coprolites placed some specimens at ages that, when calibrated to calendar years, fell in the range of approximately 14,200 to 14,300 years before present.